Complex Source and Radiation Behaviors of Small Elements of Linear and Matrix Flexible Ultrasonic Phased-Array Transducers

NASA Astrophysics Data System (ADS)

Amory, V.; Lhémery, A.

2008-02-01

Inspection of irregular components is problematical: maladjustment of transducer shoes to surfaces causes aberrations. Flexible phased-arrays (FPAs) designed at CEA LIST to maximize contact are driven by adapted delay laws to compensate for irregularities. Optimizing FPA requires simulation tools. The behavior of one element computed by FEM is observed at the surface and its radiation experimentally validated. Efforts for one element prevent from simulating a FPA by FEM. A model is proposed where each element behaves as nonuniform source of stresses. Exact and asymptotic formulas for Lamb problem are used as convolution kernels for longitudinal, transverse and head waves; the latter is of primary importance for angle-T-beam inspections.

Eddy current standards - Cracks versus notches

NASA Astrophysics Data System (ADS)

Hagemaier, D. J.; Collingwood, M. R.; Nguyen, K. H.

1992-10-01

Eddy current tests aimed at evaluating cracks and electron-discharge machined (EDM) notches in 7075-T6 aluminum specimens are described. A comparison of the shape and amplitude of recordings made from both transverse and longitudinal scans of small EDM notches and fatigue cracks showd almost identical results. The signal amplitude and phase angle increased with an increase of EDM notch and crak size. It is concluded that equivalent eddy current results obtained from similar-size surface cracks and notches in aluminum can be used to establish a desired sensitivity level for inspection.

Efficient Computation of Coherent Synchrotron Radiation Taking into Account 6D Phase Space Distribution of Emitting Electrons

NASA Astrophysics Data System (ADS)

Chubar, O.; Couprie, M.-E.

2007-01-01

CPU-efficient method for calculation of the frequency domain electric field of Coherent Synchrotron Radiation (CSR) taking into account 6D phase space distribution of electrons in a bunch is proposed. As an application example, calculation results of the CSR emitted by an electron bunch with small longitudinal and large transverse sizes are presented. Such situation can be realized in storage rings or ERLs by transverse deflection of the electron bunches in special crab-type RF cavities, i.e. using the technique proposed for the generation of femtosecond X-ray pulses (A. Zholents et. al., 1999). The computation, performed for the parameters of the SOLEIL storage ring, shows that if the transverse size of electron bunch is larger than the diffraction limit for single-electron SR at a given wavelength — this affects the angular distribution of the CSR at this wavelength and reduces the coherent flux. Nevertheless, for transverse bunch dimensions up to several millimeters and a longitudinal bunch size smaller than hundred micrometers, the resulting CSR flux in the far infrared spectral range is still many orders of magnitude higher than the flux of incoherent SR, and therefore can be considered for practical use.

Optimized coordination of brakes and active steering for a 4WS passenger car.

PubMed

Tavasoli, Ali; Naraghi, Mahyar; Shakeri, Heman

2012-09-01

Optimum coordination of individual brakes and front/rear steering subsystems is presented. The integrated control strategy consists of three modules. A coordinated high-level control determines the body forces/moment required to achieve vehicle motion objectives. The body forces/moment are allocated to braking and steering subsystems through an intermediate unit, which integrates available subsystems based on phase plane notion in an optimal manner. To this end, an optimization problem including several equality and inequality constraints is defined and solved analytically, such that a real-time implementation can be realized without the use of numeric optimization software. A low-level slip-ratio controller works to generate the desired longitudinal forces at small longitudinal slip-ratios, while averting wheel locking at large slip-ratios. The efficiency of the suggested approach is demonstrated through computer simulations. Copyright © 2012 ISA. Published by Elsevier Ltd. All rights reserved.

Generalized extended Navier-Stokes theory: correlations in molecular fluids with intrinsic angular momentum.

PubMed

Hansen, J S; Daivis, Peter J; Dyre, Jeppe C; Todd, B D; Bruus, Henrik

2013-01-21

The extended Navier-Stokes theory accounts for the coupling between the translational and rotational molecular degrees of freedom. In this paper, we generalize this theory to non-zero frequencies and wavevectors, which enables a new study of spatio-temporal correlation phenomena present in molecular fluids. To discuss these phenomena in detail, molecular dynamics simulations of molecular chlorine are performed for three different state points. In general, the theory captures the behavior for small wavevector and frequencies as expected. For example, in the hydrodynamic regime and for molecular fluids with small moment of inertia like chlorine, the theory predicts that the longitudinal and transverse intrinsic angular velocity correlation functions are almost identical, which is also seen in the molecular dynamics simulations. However, the theory fails at large wavevector and frequencies. To account for the correlations at these scales, we derive a phenomenological expression for the frequency dependent rotational viscosity and wavevector and frequency dependent longitudinal spin viscosity. From this we observe a significant coupling enhancement between the molecular angular velocity and translational velocity for large frequencies in the gas phase; this is not observed for the supercritical fluid and liquid state points.

Analysis of Wind Tunnel Longitudinal Static and Oscillatory Data of the F-16XL Aircraft

NASA Technical Reports Server (NTRS)

Klein, Vladislav; Murphy, Patrick C.; Curry, Timothy J.; Brandon, Jay M.

1997-01-01

Static and oscillatory wind tunnel data are presented for a 10-percent-scale model of an F-16XL aircraft. Static data include the effect of angle of attack, sideslip angle, and control surface deflections on aerodynamic coefficients. Dynamic data from small-amplitude oscillatory tests are presented at nominal values of angle of attack between 20 and 60 degrees. Model oscillations were performed at five frequencies from 0.6 to 2.9 Hz and one amplitude of 5 degrees. A simple harmonic analysis of the oscillatory data provided Fourier coefficients associated with the in-phase and out-of-phase components of the aerodynamic coefficients. A strong dependence of the oscillatory data on frequency led to the development of models with unsteady terms in the form of indicial functions. Two models expressing the variation of the in-phase and out-of-phase components with angle of attack and frequency were proposed and their parameters estimated from measured data.

Floating phase in the one-dimensional transverse axial next-nearest-neighbor Ising model.

PubMed

Chandra, Anjan Kumar; Dasgupta, Subinay

2007-02-01

To study the ground state of an axial next-nearest-neighbor Ising chain under transverse field as a function of frustration parameter kappa and field strength Gamma, we present here two different perturbative analyses. In one, we consider the (known) ground state at kappa=0.5 and Gamma=0 as the unperturbed state and treat an increase of the field from 0 to Gamma coupled with an increase of kappa from 0.5 to 0.5+rGamma/J as perturbation. The first-order perturbation correction to eigenvalue can be calculated exactly and we could conclude that there are only two phase-transition lines emanating from the point kappa=0.5, Gamma=0. In the second perturbation scheme, we consider the number of domains of length 1 as the perturbation and obtain the zeroth-order eigenfunction for the perturbed ground state. From the longitudinal spin-spin correlation, we conclude that floating phase exists for small values of transverse field over the entire region intermediate between the ferromagnetic phase and antiphase.

Beyond the Quantum Hall Effect: New Phases of 2D Electrons at High Magnetic Field

NASA Astrophysics Data System (ADS)

Eisenstein, James

2007-03-01

In this talk I will discuss recent experiments on high mobility single and double layer 2D electron systems in which collective phases lying outside the usual quantum Hall effect paradigm have been detected and studied. For example, in single layer 2D systems near half-filling of highly excited Landau levels new states characterized by a massive anisotropy in the electrical resistivity of the sample are observed at very low temperature. The anisotropy has been widely interpreted as the signature of a new class of correlated electron phases which incorporate a stripe-like charge density modulation. Orientational ordering of small striped domains at low temperatures accounts for the resistive anisotropy and is reminiscent of the isotropic-to-nematic phase transition in classical liquid crystals. Double layer 2D electron systems possess collective phases not present in single layer systems. In particular, when the total number of electrons in the bilayer equals the degeneracy of a single Landau level, an unusual phase appears at small layer separation. This phase possesses a novel broken symmetry, spontaneous interlayer phase coherence, which has a number of dramatic experimental signatures. The interlayer tunneling conductance develops a strong and very sharp resonance around zero bias resembling the dc Josephson effect. At the same time, both the longitudinal and Hall resistances of the sample vanish at low temperatures when currents are driven in opposite directions through the two layers. These, and other observations are broadly consistent with theories in which the broken symmetry phase can equivalently be described as a pseudospin ferromagnet or an (imperfect) excitonic superfluid. This work reflects a collaboration with M.P. Lilly, K.B. Cooper, I.B. Spielman, M. Kellogg, L.A. Tracy, L.N. Pfeiffer, and K.W. West.

Termination unit

DOEpatents

Traeholt, Chresten [Frederiksberg, DK; Willen, Dag [Klagshamn, SE; Roden, Mark [Newnan, GA; Tolbert, Jerry C [Carrollton, GA; Lindsay, David [Carrollton, GA; Fisher, Paul W [Heiskell, TN; Nielsen, Carsten Thidemann [Jaegerspris, DK

2014-01-07

This invention relates to a termination unit comprising an end-section of a cable. The end section of the cable defines a central longitudinal axis and comprising end-parts of N electrical phases, an end-part of a neutral conductor and a surrounding thermally insulation envelope adapted to comprising a cooling fluid. The end-parts of the N electrical phases and the end-part of the neutral conductor each comprising at least one electrical conductor and being arranged in the cable concentrically around a core former with a phase 1 located relatively innermost, and phase N relatively outermost in the cable, phase N being surrounded by the neutral conductor, electrical insulation being arrange between neighboring electrical phases and between phase N and the neutral conductor, and wherein the end-parts of the neutral conductor and the electrical phases each comprise a contacting surface electrically connected to at least one branch current lead to provide an electrical connection: The contacting surfaces each having a longitudinal extension, and being located sequentially along the longitudinal extension of the end-section of the cable. The branch current leads being individually insulated from said thermally insulation envelope by individual electrical insulators.

Trajectories of electrons with large longitudinal momenta in the phase plane during surfatron acceleration by an electromagnetic wave

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mkrtichyan, G. S., E-mail: hay-13@mail.ru

2015-07-15

The trajectories of electrons with large longitudinal momenta in the phase plane in the course of their surfatron acceleration by an electromagnetic wave propagating in space plasma across the external magnetic field are analyzed. Electrons with large longitudinal momenta are trapped immediately if the initial wave phase Ψ(0) on the particle trajectory is positive. For negative values of Ψ(0), no electrons trapping by the wave is observed over the available computational times. According to numerical calculations, the trajectories of trapped particles in the phase plane have a singular point of the stable focus type and the behavior of the trajectorymore » corresponds to the motion in a complex nonstationary effective potential well. For some initial phases, electrons are confined in the region of the accelerating electric field for relatively short time, the energy gain being about 50–130% and more.« less

Vibration Measurement on Reticular Lamina and Basilar Membrane at Multiple Longitudinal Locations

NASA Astrophysics Data System (ADS)

Chen, Fangyi; Zha, Dingjun; Choudhury, Niloy; Fridberger, Anders; Nuttall, Alfred L.

2011-11-01

The longitudinal distribution of the organ of Corti vibration is important for both understanding the energy delivery and the timing of the cochlear amplification. Recent development on low coherence interferomtry technique allows measuring vibration inside the cochlea. The reticular lamina (RL) vibration spectrum demonstrates that RL vibration leads the basilar membrane (BM). This phase lead is consistent with the idea that the active process may lead the BM vibration. In this study, measurements on multiple longitudinal locations demonstrated similar phase lead. Results on this study suggests that there may be another longitudinal coupling mechanism inside the cochlea other than the traveling wave on BM.

Magnus-induced dynamics of driven skyrmions on a quasi-one-dimensional periodic substrate

NASA Astrophysics Data System (ADS)

Reichhardt, C.; Reichhardt, C. J. Olson

2016-09-01

We numerically examine driven skyrmions interacting with a periodic quasi-one-dimensional substrate where the driving force is applied either parallel or perpendicular to the substrate periodicity direction. For perpendicular driving, the particles in a purely overdamped system simply slide along the substrate minima; however, for skyrmions where the Magnus force is relevant, we find that a rich variety of dynamics can arise. In the single skyrmion limit, the skyrmion motion is locked along the driving or longitudinal direction for low drives, while at higher drives a transition occurs to a state in which the skyrmion moves both transverse and longitudinal to the driving direction. Within the longitudinally locked phase we find a pronounced speedup effect that occurs when the Magnus force aligns with the external driving force, while at the transition to transverse and longitudinal motion, the skyrmion velocity drops, producing negative differential conductivity. For collectively interacting skyrmion assemblies, the speedup effect is still present and we observe a number of distinct dynamical phases, including a sliding smectic phase, a disordered or moving liquid phase, a moving hexatic phase, and a moving crystal phase. The transitions between the dynamic phases produce distinct features in the structure of the skyrmion lattice and in the velocity-force curves. We map these different phases as a function of the ratio of the Magnus term to the dissipative term, the substrate strength, the commensurability ratio, and the magnitude of the driving force.

The Effect of a Twisted Magnetic Field on the Phase Mixing of the Kink Magnetohydrodynamic Waves in Coronal Loops

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ebrahimi, Zanyar; Karami, Kayoomars; Soler, Roberto, E-mail: z.ebrahimi@uok.ac.ir

There is observational evidence for the existence of a twisted magnetic field in the solar corona. This inspires us to investigate the effect of a twisted magnetic field on the evolution of magnetohydrodynamic (MHD) kink waves in coronal loops. With this aim, we solve the incompressible linearized MHD equations in a magnetically twisted nonuniform coronal flux tube in the limit of long wavelengths. Our results show that a twisted magnetic field can enhance or diminish the rate of phase mixing of the Alfvén continuum modes and the decay rate of the global kink oscillation depending on the twist model andmore » the sign of the longitudinal ( k{sub z} ) and azimuthal ( m ) wavenumbers. Also, our results confirm that in the presence of a twisted magnetic field, when the sign of one of the two wavenumbers m and k {sub z} is changed, the symmetry with respect to the propagation direction is broken. Even a small amount of twist can have an important impact on the process of energy cascading to small scales.« less

Skin dose in longitudinal and transverse linac-MRIs using Monte Carlo and realistic 3D MRI field models.

PubMed

Keyvanloo, A; Burke, B; Warkentin, B; Tadic, T; Rathee, S; Kirkby, C; Santos, D M; Fallone, B G

2012-10-01

The magnetic fields of linac-MR systems modify the path of contaminant electrons in photon beams, which alters patient skin dose. To accurately quantify the magnitude of changes in skin dose, the authors use Monte Carlo calculations that incorporate realistic 3D magnetic field models of longitudinal and transverse linac-MR systems. Finite element method (FEM) is used to generate complete 3D magnetic field maps for 0.56 T longitudinal and transverse linac-MR magnet assemblies, as well as for representative 0.5 and 1.0 T Helmholtz MRI systems. EGSnrc simulations implementing these 3D magnetic fields are performed. The geometry for the BEAMnrc simulations incorporates the Varian 600C 6 MV linac, magnet poles, the yoke, and the magnetic shields of the linac-MRIs. Resulting phase-space files are used to calculate the central axis percent depth-doses in a water phantom and 2D skin dose distributions for 70 μm entrance and exit layers using DOSXYZnrc. For comparison, skin doses are also calculated in the absence of magnetic field, and using a 1D magnetic field with an unrealistically large fringe field. The effects of photon field size, air gap (longitudinal configuration), and angle of obliquity (transverse configuration) are also investigated. Realistic modeling of the 3D magnetic fields shows that fringe fields decay rapidly and have a very small magnitude at the linac head. As a result, longitudinal linac-MR systems mostly confine contaminant electrons that are generated in the air gap and have an insignificant effect on electrons produced further upstream. The increase in the skin dose for the longitudinal configuration compared to the zero B-field case varies from ∼1% to ∼14% for air gaps of 5-31 cm, respectively. (All dose changes are reported as a % of D(max).) The increase is also field-size dependent, ranging from ∼3% at 20 × 20 cm(2) to ∼11% at 5 × 5 cm(2). The small changes in skin dose are in contrast to significant increases that are calculated for the unrealistic 1D magnetic field. For the transverse configuration, the entrance skin dose is equal or smaller than that of the zero B-field case for perpendicular beams. For a 10 × 10 cm(2) oblique beam the transverse magnetic field decreases the entry skin dose for oblique angles less than ±20° and increases it by no more than 10% for larger angles up to ±45°. The exit skin dose is increased by 42% for a 10 × 10 cm(2) perpendicular beam, but appreciably drops and approaches the zero B-field case for large oblique angles of incidence. For longitudinal linac-MR systems only a small increase in the entrance skin dose is predicted, due to the rapid decay of the realistic magnetic fringe fields. For transverse linac-MR systems, changes to the entrance skin dose are small for most scenarios. For the same geometry, on the exit side a fairly large increase is observed for perpendicular beams, but significantly drops for large oblique angles of incidence. The observed effects on skin dose are not expected to limit the application of linac-MR systems in either the longitudinal or transverse configuration.

Longitudinal phase-space coating of beam in a storage ring

NASA Astrophysics Data System (ADS)

Bhat, C. M.

2014-06-01

In this Letter, I report on a novel scheme for beam stacking without any beam emittance dilution using a barrier rf system in synchrotrons. The general principle of the scheme called longitudinal phase-space coating, validation of the concept via multi-particle beam dynamics simulations applied to the Fermilab Recycler, and its experimental demonstration are presented. In addition, it has been shown and illustrated that the rf gymnastics involved in this scheme can be used in measuring the incoherent synchrotron tune spectrum of the beam in barrier buckets and in producing a clean hollow beam in longitudinal phase space. The method of beam stacking in synchrotrons presented here is the first of its kind.

Investigating Stage-Sequential Growth Mixture Models with Multiphase Longitudinal Data

ERIC Educational Resources Information Center

Kim, Su-Young; Kim, Jee-Seon

2012-01-01

This article investigates three types of stage-sequential growth mixture models in the structural equation modeling framework for the analysis of multiple-phase longitudinal data. These models can be important tools for situations in which a single-phase growth mixture model produces distorted results and can allow researchers to better understand…

Longitudinal Variation of the Lunar Tide in the Equatorial Electrojet

NASA Astrophysics Data System (ADS)

Yamazaki, Yosuke; Stolle, Claudia; Matzka, Jürgen; Siddiqui, Tarique A.; Lühr, Hermann; Alken, Patrick

2017-12-01

The atmospheric lunar tide is one known source of ionospheric variability. The subject received renewed attention as recent studies found a link between stratospheric sudden warmings and amplified lunar tidal perturbations in the equatorial ionosphere. There is increasing evidence from ground observations that the lunar tidal influence on the ionosphere depends on longitude. We use magnetic field measurements from the CHAMP satellite during July 2000 to September 2010 and from the two Swarm satellites during November 2013 to February 2017 to determine, for the first time, the complete seasonal-longitudinal climatology of the semidiurnal lunar tidal variation in the equatorial electrojet intensity. Significant longitudinal variability is found in the amplitude of the lunar tidal variation, while the longitudinal variability in the phase is small. The amplitude peaks in the Peruvian sector (˜285°E) during the Northern Hemisphere winter and equinoxes, and in the Brazilian sector (˜325°E) during the Northern Hemisphere summer. There are also local amplitude maxima at ˜55°E and ˜120°E. The longitudinal variation is partly due to the modulation of ionospheric conductivities by the inhomogeneous geomagnetic field. Another possible cause of the longitudinal variability is neutral wind forcing by nonmigrating lunar tides. A tidal spectrum analysis of the semidiurnal lunar tidal variation in the equatorial electrojet reveals the dominance of the westward propagating mode with zonal wave number 2 (SW2), with secondary contributions by westward propagating modes with zonal wave numbers 3 (SW3) and 4 (SW4). Eastward propagating waves are largely absent from the tidal spectrum. Further study will be required for the relative importance of ionospheric conductivities and nonmigrating lunar tides.

Symmetry energy in cold dense matter

NASA Astrophysics Data System (ADS)

Jeong, Kie Sang; Lee, Su Houng

2016-01-01

We calculate the symmetry energy in cold dense matter both in the normal quark phase and in the 2-color superconductor (2SC) phase. For the normal phase, the thermodynamic potential is calculated by using hard dense loop (HDL) resummation to leading order, where the dominant contribution comes from the longitudinal gluon rest mass. The effect of gluonic interaction on the symmetry energy, obtained from the thermodynamic potential, was found to be small. In the 2SC phase, the non-perturbative BCS paring gives enhanced symmetry energy as the gapped states are forced to be in the common Fermi sea reducing the number of available quarks that can contribute to the asymmetry. We used high density effective field theory to estimate the contribution of gluon interaction to the symmetry energy. Among the gluon rest masses in 2SC phase, only the Meissner mass has iso-spin dependence although the magnitude is much smaller than the Debye mass. As the iso-spin dependence of gluon rest masses is even smaller than the case in the normal phase, we expect that the contribution of gluonic interaction to the symmetry energy in the 2SC phase will be minimal. The different value of symmetry energy in each phase will lead to different prediction for the particle yields in heavy ion collision experiment.

Conditional sampling technique to test the applicability of the Taylor hypothesis for the large-scale coherent structures

NASA Technical Reports Server (NTRS)

Hussain, A. K. M. F.

1980-01-01

Comparisons of the distributions of large scale structures in turbulent flow with distributions based on time dependent signals from stationary probes and the Taylor hypothesis are presented. The study investigated an area in the near field of a 7.62 cm circular air jet at a Re of 32,000, specifically having coherent structures through small-amplitude controlled excitation and stable vortex pairing in the jet column mode. Hot-wire and X-wire anemometry were employed to establish phase averaged spatial distributions of longitudinal and lateral velocities, coherent Reynolds stress and vorticity, background turbulent intensities, streamlines and pseudo-stream functions. The Taylor hypothesis was used to calculate spatial distributions of the phase-averaged properties, with results indicating that the usage of the local time-average velocity or streamwise velocity produces large distortions.

Theoretical Analysis of the Longitudinal Behavior of an Automatically Controlled Supersonic Interceptor During the Attack Phase

NASA Technical Reports Server (NTRS)

Gates, Ordway B., Jr.; Woodling, C. H.

1959-01-01

Theoretical analysis of the longitudinal behavior of an automatically controlled supersonic interceptor during the attack phase against a nonmaneuvering target is presented. Control of the interceptor's flight path is obtained by use of a pitch rate command system. Topics lift, and pitching moment, effects of initial tracking errors, discussion of normal acceleration limited, limitations of control surface rate and deflection, and effects of neglecting forward velocity changes of interceptor during attack phase.

Pbar Beam Stacking in the Recycler by Longitudinal Phase-space Coating

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bhat, C. M.

2013-08-06

Barrier rf buckets have brought about new challenges in longitudinal beam dynamics of charged particle beams in synchrotrons and at the same time led to many new remarkable prospects in beam handling. In this paper, I describe a novel beam stacking scheme for synchrotrons using barrier buckets without any emittance dilution to the beam. First I discuss the general principle of the method, called longitudinal phase-space coating. Multi-particle beam dynamics simulations of the scheme applied to the Recycler, convincingly validates the concepts and feasibility of the method. Then I demonstrate the technique experimentally in the Recycler and also use itmore » in operation. A spin-off of this scheme is its usefulness in mapping the incoherent synchrotron tune spectrum of the beam particles in barrier buckets and producing a clean hollow beam in longitudinal phase space. Both of which are described here in detail with illustrations. The beam stacking scheme presented here is the first of its kind.« less

Three-dimensional envelope instability in periodic focusing channels

NASA Astrophysics Data System (ADS)

Qiang, Ji

2018-03-01

The space-charge driven envelope instability can be of great danger in high intensity accelerators and was studied using a two-dimensional (2D) envelope model and three-dimensional (3D) macroparticle simulations before. In this paper, we study the instability for a bunched beam using a three-dimensional envelope model in a periodic solenoid and radio-frequency (rf) focusing channel and a periodic quadrupole and rf focusing channel. This study shows that when the transverse zero current phase advance is below 90 ° , the beam envelope can still become unstable if the longitudinal zero current phase advance is beyond 90 ° . For the transverse zero current phase advance beyond 90 ° , the instability stopband width becomes larger with the increase of the longitudinal focusing strength and even shows different structure from the 2D case when the longitudinal zero current phase advance is beyond 90 ° . Breaking the symmetry of two longitudinal focusing rf cavities and the symmetry between the horizontal focusing and the vertical focusing in the transverse plane in the periodic quadrupole and rf channel makes the instability stopband broader. This suggests that a more symmetric accelerator lattice design might help reduce the range of the envelope instability in parameter space.

A multiphase non-linear mixed effects model: An application to spirometry after lung transplantation.

PubMed

Rajeswaran, Jeevanantham; Blackstone, Eugene H

2017-02-01

In medical sciences, we often encounter longitudinal temporal relationships that are non-linear in nature. The influence of risk factors may also change across longitudinal follow-up. A system of multiphase non-linear mixed effects model is presented to model temporal patterns of longitudinal continuous measurements, with temporal decomposition to identify the phases and risk factors within each phase. Application of this model is illustrated using spirometry data after lung transplantation using readily available statistical software. This application illustrates the usefulness of our flexible model when dealing with complex non-linear patterns and time-varying coefficients.

Wide-range high-resolution transmission electron microscopy reveals morphological and distributional changes of endomembrane compartments during log to stationary transition of growth phase in tobacco BY-2 cells.

PubMed

Toyooka, Kiminori; Sato, Mayuko; Kutsuna, Natsumaro; Higaki, Takumi; Sawaki, Fumie; Wakazaki, Mayumi; Goto, Yumi; Hasezawa, Seiichiro; Nagata, Noriko; Matsuoka, Ken

2014-09-01

Rapid growth of plant cells by cell division and expansion requires an endomembrane trafficking system. The endomembrane compartments, such as the Golgi stacks, endosome and vesicles, are important in the synthesis and trafficking of cell wall materials during cell elongation. However, changes in the morphology, distribution and number of these compartments during the different stages of cell proliferation and differentiation have not yet been clarified. In this study, we examined these changes at the ultrastructural level in tobacco Bright yellow 2 (BY-2) cells during the log and stationary phases of growth. We analyzed images of the BY-2 cells prepared by the high-pressure freezing/freeze substitution technique with the aid of an auto-acquisition transmission electron microscope system. We quantified the distribution of secretory and endosomal compartments in longitudinal sections of whole cells by using wide-range gigapixel-class images obtained by merging thousands of transmission electron micrographs. During the log phase, all Golgi stacks were composed of several thick cisternae. Approximately 20 vesicle clusters (VCs), including the trans-Golgi network and secretory vesicle cluster, were observed throughout the cell. In the stationary-phase cells, Golgi stacks were thin with small cisternae, and only a few VCs were observed. Nearly the same number of multivesicular body and small high-density vesicles were observed in both the stationary and log phases. Results from electron microscopy and live fluorescence imaging indicate that the morphology and distribution of secretory-related compartments dramatically change when cells transition from log to stationary phases of growth. © The Author 2014. Published by Oxford University Press on behalf of Japanese Society of Plant Physiologists. All rights reserved. For permissions, please email: journals.permissions@oup.com.

Cochlear microphonic broad tuning curves

NASA Astrophysics Data System (ADS)

Ayat, Mohammad; Teal, Paul D.; Searchfield, Grant D.; Razali, Najwani

2015-12-01

It is known that the cochlear microphonic voltage exhibits much broader tuning than does the basilar membrane motion. The most commonly used explanation for this is that when an electrode is inserted at a particular point inside the scala media, the microphonic potentials of neighbouring hair cells have different phases, leading to cancelation at the electrodes location. In situ recording of functioning outer hair cells (OHCs) for investigating this hypothesis is exceptionally difficult. Therefore, to investigate the discrepancy between the tuning curves of the basilar membrane and those of the cochlear microphonic, and the effect of phase cancellation of adjacent hair cells on the broadness of the cochlear microphonic tuning curves, we use an electromechanical model of the cochlea to devise an experiment. We explore the effect of adjacent hair cells (i.e., longitudinal phase cancellation) on the broadness of the cochlear microphonic tuning curves in different locations. The results of the experiment indicate that active longitudinal coupling (i.e., coupling with active adjacent outer hair cells) only slightly changes the broadness of the CM tuning curves. The results also demonstrate that there is a π phase difference between the potentials produced by the hair bundle and the soma near the place associated with the characteristic frequency based on place-frequency maps (i.e., the best place). We suggest that the transversal phase cancellation (caused by the phase difference between the hair bundle and the soma) plays a far more important role than longitudinal phase cancellation in the broadness of the cochlear microphonic tuning curves. Moreover, by increasing the modelled longitudinal resistance resulting the cochlear microphonic curves exhibiting sharper tuning. The results of the simulations suggest that the passive network of the organ of Corti determines the phase difference between the hair bundle and soma, and hence determines the sharpness of the cochlear microphonic tuning curves.

Enhanced dynamical stability with harmonic slip stacking

DOE PAGES

Eldred, Jeffrey; Zwaska, Robert

2016-10-26

We develop a configuration of radio-frequency (rf) cavities to dramatically improve the performance of slip-stacking. Slip-stacking is an accumulation technique used at Fermilab to nearly double proton intensity by maintaining two beams of different momenta in the same storage ring. The two particle beams are longitudinally focused in the Recycler by two 53 MHz 100 kV rf cavities with a small frequency difference between them. We propose an additional 106 MHz 20 kV rf cavity with a frequency at the double the average of the upper and lower main rf frequencies. We show the harmonic rf cavity cancels out themore » resonances generated between the two main rf cavities and we derive the relationship between the harmonic rf voltage and the main rf voltage. We find the area factors that can be used to calculate the available phase space area for any set of beam parameters without individual simulation. We establish Booster beam quality requirements to achieve 99\\% slip-stacking efficiency. We measure the longitudinal distribution of the Booster beam and use it to generate a realistic beam model for slip-stacking simulation. In conclusion, we demonstrate that the harmonic rf cavity can not only reduce particle loss during slip-stacking, but also reduce the final longitudinal emittance.« less

Enhanced dynamical stability with harmonic slip stacking

DOE Office of Scientific and Technical Information (OSTI.GOV)

Eldred, Jeffrey; Zwaska, Robert

We develop a configuration of radio-frequency (rf) cavities to dramatically improve the performance of slip-stacking. Slip-stacking is an accumulation technique used at Fermilab to nearly double proton intensity by maintaining two beams of different momenta in the same storage ring. The two particle beams are longitudinally focused in the Recycler by two 53 MHz 100 kV rf cavities with a small frequency difference between them. We propose an additional 106 MHz 20 kV rf cavity with a frequency at the double the average of the upper and lower main rf frequencies. We show the harmonic rf cavity cancels out themore » resonances generated between the two main rf cavities and we derive the relationship between the harmonic rf voltage and the main rf voltage. We find the area factors that can be used to calculate the available phase space area for any set of beam parameters without individual simulation. We establish Booster beam quality requirements to achieve 99\\% slip-stacking efficiency. We measure the longitudinal distribution of the Booster beam and use it to generate a realistic beam model for slip-stacking simulation. In conclusion, we demonstrate that the harmonic rf cavity can not only reduce particle loss during slip-stacking, but also reduce the final longitudinal emittance.« less

Relaxation rates of low-field gas-phase ^129Xe storage cells

NASA Astrophysics Data System (ADS)

Limes, Mark; Saam, Brian

2010-10-01

A study of longitudinal nuclear relaxation rates T1 of ^129Xe and Xe-N2 mixtures in a magnetic field of 3.8 mT is presented. In this regime, intrinsic spin relaxation is dominated by the intramolecular spin-rotation interaction due to persistent xenon dimers, a mechanism that can be quelled by introducing large amounts of N2 into the storage cell. Extrinsic spin relaxation is dominated by the wall-relaxation rate, which is the primary quantity of interest for the various low-field storage cells and coatings that we have tested. Previous group work has shown that extremely long gas-phase relaxation times T1 can be obtained, but only at large magnetic fields and low xenon densities. The current work is motivated by the practical benefits of retaining hyperpolarized ^129Xe for extended periods of time in a small magnetic field.

Towards an integrated AlGaAs waveguide platform for phase and polarisation shaping

NASA Astrophysics Data System (ADS)

Maltese, G.; Halioua, Y.; Lemaître, A.; Gomez-Carbonell, C.; Karimi, E.; Banzer, P.; Ducci, S.

2018-05-01

We propose, design and fabricate an on-chip AlGaAs waveguide capable of generating a controlled phase delay of π/2 between the guided transverse electric and magnetic modes. These modes possess significantly strong longitudinal field components as a direct consequence of their strong lateral confinement in the waveguide. We demonstrate that the effect of the device on a linearly polarised input beam is the generation of a field, which is circularly polarised in its transverse components and carries a phase vortex in its longitudinal component. We believe that the discussed integrated platform enables the generation of light beams with tailored phase and polarisation distributions.

Seismic shear waves as Foucault pendulum

NASA Astrophysics Data System (ADS)

Snieder, Roel; Sens-Schönfelder, Christoph; Ruigrok, Elmer; Shiomi, Katsuhiko

2016-03-01

Earth's rotation causes splitting of normal modes. Wave fronts and rays are, however, not affected by Earth's rotation, as we show theoretically and with observations made with USArray. We derive that the Coriolis force causes a small transverse component for P waves and a small longitudinal component for S waves. More importantly, Earth's rotation leads to a slow rotation of the transverse polarization of S waves; during the propagation of S waves the particle motion behaves just like a Foucault pendulum. The polarization plane of shear waves counteracts Earth's rotation and rotates clockwise in the Northern Hemisphere. The rotation rate is independent of the wave frequency and is purely geometric, like the Berry phase. Using the polarization of ScS and ScS2 waves, we show that the Foucault-like rotation of the S wave polarization can be observed. This can affect the determination of source mechanisms and the interpretation of observed SKS splitting.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Noda, Akira; Iwashita, Yoshihisa; Souda, Hikaru

A phase rotation scheme of laser-produced ions from a solid target by the application of a synchronized RF electric voltage with a pulsed laser has been experimentally investigated with the use of a 100 TW laser, J-KAREN at JAEA, KPSI. Up to now, energy peaks of up to around 2.0 MeV have been created with a FWHM of 2.6% with good reproducibility using a two-gap resonator of a quarter wave length with the same frequency as the source laser (approx80 MHz). It is also found that the position of the peak can be well controlled by adjusting the relative phasemore » between the RF electric field and the laser, which is very promising for real applications of such laser-produced protons. In order to also apply such a phase rotation system for higher energy protons (<200 MeV), a scheme to use a small linear accelerator (LINAC) with multi-gaps is proposed as a phase rotator. With multi-gap structure, alternating focusing between longitudinal and transverse degrees of freedoms can be realized. From the point of compactness and realizing a small focused spot, however, a scheme combining separate quadrupole magnets just before and after the RF cavity excited with the Wideroee mode, might be more effective. The scheme presented here will realize laser-produced ions (protons) with good reproducibility by combining with RF technology.« less

Curvature reduces bending strains in the quokka femur

PubMed Central

McCabe, Kyle; Henderson, Keith; Pantinople, Jess; Milne, Nick

2017-01-01

This study explores how curvature in the quokka femur may help to reduce bending strain during locomotion. The quokka is a small wallaby, but the curvature of the femur and the muscles active during stance phase are similar to most quadrupedal mammals. Our hypothesis is that the action of hip extensor and ankle plantarflexor muscles during stance phase place cranial bending strains that act to reduce the caudal curvature of the femur. Knee extensors and biarticular muscles that span the femur longitudinally create caudal bending strains in the caudally curved (concave caudal side) bone. These opposing strains can balance each other and result in less strain on the bone. We test this idea by comparing the performance of a normally curved finite element model of the quokka femur to a digitally straightened version of the same bone. The normally curved model is indeed less strained than the straightened version. To further examine the relationship between curvature and the strains in the femoral models, we also tested an extra-curved and a reverse-curved version with the same loads. There appears to be a linear relationship between the curvature and the strains experienced by the models. These results demonstrate that longitudinal curvature in bones may be a manipulable mechanism whereby bone can induce a strain gradient to oppose strains induced by habitual loading. PMID:28348929

A Multiphase Non-Linear Mixed Effects Model: An Application to Spirometry after Lung Transplantation

PubMed Central

Rajeswaran, Jeevanantham; Blackstone, Eugene H.

2014-01-01

In medical sciences, we often encounter longitudinal temporal relationships that are non-linear in nature. The influence of risk factors may also change across longitudinal follow-up. A system of multiphase non-linear mixed effects model is presented to model temporal patterns of longitudinal continuous measurements, with temporal decomposition to identify the phases and risk factors within each phase. Application of this model is illustrated using spirometry data after lung transplantation using readily available statistical software. This application illustrates the usefulness of our flexible model when dealing with complex non-linear patterns and time varying coefficients. PMID:24919830

Linear magnetoconductivity in an intrinsic topological Weyl semimetal

NASA Astrophysics Data System (ADS)

Zhang, Song-Bo; Lu, Hai-Zhou; Shen, Shun-Qing

2016-05-01

Searching for the signature of the violation of chiral charge conservation in solids has inspired a growing passion for the magneto-transport in topological semimetals. One of the open questions is how the conductivity depends on magnetic fields in a semimetal phase when the Fermi energy crosses the Weyl nodes. Here, we study both the longitudinal and transverse magnetoconductivity of a topological Weyl semimetal near the Weyl nodes with the help of a two-node model that includes all the topological semimetal properties. In the semimetal phase, the Fermi energy crosses only the 0th Landau bands in magnetic fields. For a finite potential range of impurities, it is found that both the longitudinal and transverse magnetoconductivity are positive and linear at the Weyl nodes, leading to an anisotropic and negative magnetoresistivity. The longitudinal magnetoconductivity depends on the potential range of impurities. The longitudinal conductivity remains finite at zero field, even though the density of states vanishes at the Weyl nodes. This work establishes a relation between the linear magnetoconductivity and the intrinsic topological Weyl semimetal phase.

Atmospheric and Fog Effects on Ultra-Wide Band Radar Operating at Extremely High Frequencies.

PubMed

Balal, Nezah; Pinhasi, Gad A; Pinhasi, Yosef

2016-05-23

The wide band at extremely high frequencies (EHF) above 30 GHz is applicable for high resolution directive radars, resolving the lack of free frequency bands within the lower part of the electromagnetic spectrum. Utilization of ultra-wideband signals in this EHF band is of interest, since it covers a relatively large spectrum, which is free of users, resulting in better resolution in both the longitudinal and transverse dimensions. Noting that frequencies in the millimeter band are subjected to high atmospheric attenuation and dispersion effects, a study of the degradation in the accuracy and resolution is presented. The fact that solid-state millimeter and sub-millimeter radiation sources are producing low power, the method of continuous-wave wideband frequency modulation becomes the natural technique for remote sensing and detection. Millimeter wave radars are used as complementary sensors for the detection of small radar cross-section objects under bad weather conditions, when small objects cannot be seen by optical cameras and infrared detectors. Theoretical analysis for the propagation of a wide "chirped" Frequency-Modulated Continuous-Wave (FMCW) radar signal in a dielectric medium is presented. It is shown that the frequency-dependent (complex) refractivity of the atmospheric medium causes distortions in the phase of the reflected signal, introducing noticeable errors in the longitudinal distance estimations, and at some frequencies may also degrade the resolution.

Atmospheric and Fog Effects on Ultra-Wide Band Radar Operating at Extremely High Frequencies

PubMed Central

Balal, Nezah; Pinhasi, Gad A.; Pinhasi, Yosef

2016-01-01

The wide band at extremely high frequencies (EHF) above 30 GHz is applicable for high resolution directive radars, resolving the lack of free frequency bands within the lower part of the electromagnetic spectrum. Utilization of ultra-wideband signals in this EHF band is of interest, since it covers a relatively large spectrum, which is free of users, resulting in better resolution in both the longitudinal and transverse dimensions. Noting that frequencies in the millimeter band are subjected to high atmospheric attenuation and dispersion effects, a study of the degradation in the accuracy and resolution is presented. The fact that solid-state millimeter and sub-millimeter radiation sources are producing low power, the method of continuous-wave wideband frequency modulation becomes the natural technique for remote sensing and detection. Millimeter wave radars are used as complementary sensors for the detection of small radar cross-section objects under bad weather conditions, when small objects cannot be seen by optical cameras and infrared detectors. Theoretical analysis for the propagation of a wide “chirped” Frequency-Modulated Continuous-Wave (FMCW) radar signal in a dielectric medium is presented. It is shown that the frequency-dependent (complex) refractivity of the atmospheric medium causes distortions in the phase of the reflected signal, introducing noticeable errors in the longitudinal distance estimations, and at some frequencies may also degrade the resolution. PMID:27223286

Thermoelectric Transport Signatures of Dirac Composite Fermions in the Half-Filled Landau Level

NASA Astrophysics Data System (ADS)

Potter, Andrew C.; Serbyn, Maksym; Vishwanath, Ashvin

2016-07-01

The half-filled Landau level is expected to be approximately particle-hole symmetric, which requires an extension of the Halperin-Lee-Read (HLR) theory of the compressible state observed at this filling. Recent work indicates that, when particle-hole symmetry is preserved, the composite fermions experience a quantized π -Berry phase upon winding around the composite Fermi surface, analogous to Dirac fermions at the surface of a 3D topological insulator. In contrast, the effective low-energy theory of the composite fermion liquid originally proposed by HLR lacks particle-hole symmetry and has vanishing Berry phase. In this paper, we explain how thermoelectric transport measurements can be used to test the Dirac nature of the composite fermions by quantitatively extracting this Berry phase. First, we point out that longitudinal thermopower (Seebeck effect) is nonvanishing because of the unusual nature of particle-hole symmetry in this context and is not sensitive to the Berry phase. In contrast, we find that off-diagonal thermopower (Nernst effect) is directly related to the topological structure of the composite Fermi surface, vanishing for zero Berry phase and taking its maximal value for π Berry phase. In contrast, in purely electrical transport signatures, the Berry phase contributions appear as small corrections to a large background signal, making the Nernst effect a promising diagnostic of the Dirac nature of composite fermions.

Space-charge-sustained microbunch structure in the Los Alamos Proton Storage Ring

NASA Astrophysics Data System (ADS)

Cousineau, S.; Danilov, V.; Holmes, J.; Macek, R.

2004-09-01

We present experimental data from the Los Alamos Proton Storage Ring (PSR) showing long-lived linac microbunch structure during beam storage with no rf bunching. Analysis of the experimental data and particle-in-cell simulations of the experiments indicate that space charge, coupled with energy spread effects, is responsible for the sustained microbunch structure. The simulated longitudinal phase space of the beam reveals a well-defined separatrix in the phase space between linac microbunches, with particles executing unbounded motion outside of the separatrix. We show that the longitudinal phase space of the beam was near steady state during the PSR experiments, such that the separatrix persisted for long periods of time. Our simulations indicate that the steady state is very sensitive to the experimental conditions. Finally, we solve the steady-state problem in an analytic, self-consistent fashion for a set of periodic longitudinal space-charge potentials.

Experimental study of boron-coated straws with a neutron source

NASA Astrophysics Data System (ADS)

Xie, Zhaoyang; Zhou, Jianrong; Song, Yushou; Lacy, Jeffrey L.; Sun, Liang; Sun, Zhijia; Hu, Bitao; Chen, Yuanbo

2018-04-01

Multiple types of high quality neutron detectors are proposed for the first phase of the China Spallation Neutron Source (CSNS), which will be commissioned in 2018. Considering the shortage of 3He supply, a detector module composed of 49 boron-coated straws (BCS) was developed by Proportional Technologies Inc. (PTI). Each straw has a length of 1000 mm and a diameter of 7.5 mm. Seven straws are tightly packed in a tube, and seven tubes are organized in a row to form a detector module. The charge division method is used for longitudinal positioning. A specific readout system was utilized to output the signal and simultaneously encode each straw. The performance of this detector module was studied using a moderated 252Cf source at the Institute of High Energy Physics (IHEP). The signal amplitude spectrum indicates its n-gamma discrimination capability. Despite the complex readout method, a longitudinal resolution of FWHM=6.1 ± 0.5 mm was obtained. The three-dimensional positioning ability qualifies this BCS detector module as a promising detector for small angle neutron scattering.

Optimal feeding systems for small-scale dairy herds in the North West Province, South Africa.

PubMed

Manzana, N Patience; McCrindle, Cheryl M E; Sebei, P Julius; Prozesky, Leon

2014-07-09

Land redistribution was legislated in 1994; it was designed to resolve historical imbalances inland ownership in South Africa. Between 2002 and 2006, a longitudinal observational studywas conducted with 15 purposively selected small-scale dairy farmers in a land redistributionproject in Central North West Province. Four farmers left the project over the period. For thepurposes of this study, a small-scale dairy farm was defined as a farm that produces less than500 L of milk a day, irrespective of the number of cows or size of the farm. The study wasconducted in three phases. In the first phase, situational analysis using participatory ruralappraisal (PRA) and observation was used to outline the extent of the constraints and designappropriate interventions. Feeds that were used were tested and evaluated. In the secondphase, three different feeding systems were designed from the data obtained from PRA. Thesewere: (1) A semi-intensive farm-based ration using available crops, pastures and crop residueswith minimal rations purchased. (2) An intensive, zero-grazing dairy system using a totalmixed ration. (3) A traditional, extensive or dual-purpose system, where the calf drank fromthe cow until weaning and milking was done only once a day. In the third phase, adoptionwas monitored. By July 2006, all remaining farmers had changed to commercially formulatedrations or licks and the body condition score of the cows had improved. It was concluded thatveterinary extension based on PRA and a holistic systems approach was a good option forsuch complex problems. Mentoring by commercial dairy farmers, veterinary and extensionservices appeared to be viable. Further research should be done to optimise the traditionalmodel of dairy farming, as this was relatively profitable, had a lower risk and was less labourintensive.

Influence of the porosity on the dispersion of the phase velocity of longitudinal acoustic waves in isotropic metal-matrix composites

NASA Astrophysics Data System (ADS)

Karabutov, A. A.; Podymova, N. B.

2017-05-01

The influence of the volumetric porosity of isotropic metal-matrix composite materials, which are reinforced with ceramic microparticles, on the dispersion of the phase velocity of longitudinal acoustic waves is investigated. For this purpose, the method of broadband acoustic spectroscopy with a laser source of ultrasound and piezoelectric detection of nanosecond ultrasonic pulses is used. Composite samples based on a silumin matrix with added silicon carbide (SiC) microparticles in different mass concentrations (3.8-15.5%) were investigated. As the concentration of SiC particles in a sample increases, its porosity that is determined using the hydrostatic-weighing method also increases. The simultaneous increase in the filler concentration and porosity leads to the appearance of a dispersion of the phase velocity of longitudinal acoustic waves in the sample within the frequency range of 3-25 MHz. The obtained empirical relationship between the relative change in the phase velocity and the sample porosity can be used to obtain a proximate quantitative estimate of the bulk porosity of the isotropic metal-matrix composite materials.

Magnus-induced dynamics of driven skyrmions on a quasi-one-dimensional periodic substrate

DOE PAGES

Reichhardt, Charles; Reichhardt, Cynthia Jane

2016-09-13

Here we numerically examine driven skyrmions interacting with a periodic quasi-one-dimensional substrate where the driving force is applied either parallel or perpendicular to the substrate periodicity direction. For perpendicular driving, the particles in a purely overdamped system simply slide along the substrate minima; however, for skyrmions where the Magnus force is relevant, we find that a rich variety of dynamics can arise. In the single skyrmion limit, the skyrmion motion is locked along the driving or longitudinal direction for low drives, while at higher drives a transition occurs to a state in which the skyrmion moves both transverse and longitudinalmore » to the driving direction. Within the longitudinally locked phase we find a pronounced speedup effect that occurs when the Magnus force aligns with the external driving force, while at the transition to transverse and longitudinal motion, the skyrmion velocity drops, producing negative differential conductivity. For collectively interacting skyrmion assemblies, the speedup effect is still present and we observe a number of distinct dynamical phases, including a sliding smectic phase, a disordered or moving liquid phase, a moving hexatic phase, and a moving crystal phase. The transitions between the dynamic phases produce distinct features in the structure of the skyrmion lattice and in the velocity-force curves. Lastly, we map these different phases as a function of the ratio of the Magnus term to the dissipative term, the substrate strength, the commensurability ratio, and the magnitude of the driving force.« less

Morphological MRI characteristics of recent small subcortical infarcts.

PubMed

Gattringer, Thomas; Eppinger, Sebastian; Pinter, Daniela; Pirpamer, Lukas; Berghold, Andrea; Wünsch, Gerit; Ropele, Stefan; Wardlaw, Joanna M; Enzinger, Christian; Fazekas, Franz

2015-10-01

New imaging criteria for recent small subcortical infarcts have recently been proposed, replacing the earlier term 'lacunar infarction', but their applicability and impact on lesion selection is yet unknown. To collect information on the morphologic characteristics and variability of recent small subcortical infarcts on magnetic resonance imaging in regard to lesion location and demographic variables. We identified all patients with acute stroke and cerebral magnetic resonance imaging from 2008 to 2013 in our hospital database and selected those with a single recent small subcortical infarct defined by an estimated maximal axial diameter of 20 mm. Recent small subcortical infarcts were segmented on diffusion-weighted imaging and fluid-attenuated inversion recovery sequence to calculate the largest axial and longitudinal diameter and lesion volume. We assessed morphometric differences of recent small subcortical infarcts regarding location and demographic variables and the impact of different recent small subcortical infarct definitions on lesion selection. Three hundred forty-four patients (median age 72; range 25-92 years, 65% male) were selected. Most recent small subcortical infarcts were located in the basal ganglia (n = 111), followed by pons (n = 92), thalamus (n = 77), and centrum semiovale (n = 64). Quantitative measurements confirmed visual assessment of the axial diameter in 95%. All morphometric variables were strongly intercorrelated and comparable on diffusion-weighted imaging and fluid-attenuated inversion recovery sequence. Recent small subcortical infarcts in the basal ganglia were significantly larger both in the axial and longitudinal direction compared with other regions. Dichotomization of recent small subcortical infarcts according to axial (≤ / >15 mm) or longitudinal (≤ / >20 mm) sizes resulted in different regional frequencies and distributions. Age, gender, and time from stroke onset to magnetic resonance imaging did not influence lesion metrics or the distribution of recent small subcortical infarcts. Our study confirms the recent neuroimaging criteria for recent small subcortical infarcts as a practical concept. Definitions of the maximal axial and longitudinal diameter have a significant impact on the frequency and distribution of selected infarcts, which has to be considered for future studies. © 2015 World Stroke Organization.

Photoinduced topological phase transition and spin polarization in a two-dimensional topological insulator

NASA Astrophysics Data System (ADS)

Chen, M. N.; Su, W.; Deng, M. X.; Ruan, Jiawei; Luo, W.; Shao, D. X.; Sheng, L.; Xing, D. Y.

2016-11-01

A great deal of attention has been paid to the topological phases engineered by photonics over the past few years. Here, we propose a topological quantum phase transition to a quantum anomalous Hall (QAH) phase induced by off-resonant circularly polarized light in a two-dimensional system that is initially in a quantum spin Hall phase or a trivial insulator phase. This provides an alternative method to realize the QAH effect, other than magnetic doping. The circularly polarized light effectively creates a Zeeman exchange field and a renormalized Dirac mass, which are tunable by varying the intensity of the light and drive the quantum phase transition. Both the transverse and longitudinal Hall conductivities are studied, and the former is consistent with the topological phase transition when the Fermi level lies in the band gap. A highly controllable spin-polarized longitudinal electrical current can be generated when the Fermi level is in the conduction band, which may be useful for designing topological spintronics.

Critical behavior of a quantum chain with four-spin interactions in the presence of longitudinal and transverse magnetic fields.

PubMed

Boechat, B; Florencio, J; Saguia, A; de Alcantara Bonfim, O F

2014-03-01

We study the ground-state properties of a spin-1/2 model on a chain containing four-spin Ising-like interactions in the presence of both transverse and longitudinal magnetic fields. We use entanglement entropy and finite-size scaling methods to obtain the phase diagrams of the model. Our numerical calculations reveal a rich variety of phases and the existence of multicritical points in the system. We identify phases with both ferromagnetic and antiferromagnetic orderings. We also find periodically modulated orderings formed by a cluster of like spins followed by another cluster of opposite like spins. The quantum phases in the model are found to be separated by either first- or second-order transition lines.

Handling Qualities of a Large Civil Tiltrotor in Hover using Translational Rate Command

NASA Technical Reports Server (NTRS)

Malpica, Carlos A.; Theodore, Colin R.; Lawrence, Ben; Lindsey, James; Blanken, Chris

2012-01-01

A Translational Rate Command (TRC) control law has been developed to enable low speed maneuvering of a large civil tiltrotor with minimal pitch changes by means of automatic nacelle angle deflections for longitudinal velocity control. The nacelle actuator bandwidth required to achieve Level 1 handling qualities in hover and the feasibility of additional longitudinal cyclic control to augment low bandwidth nacelle actuation were investigated. A frequency-domain handling qualities criterion characterizing TRC response in terms of bandwidth and phase delay was proposed and validated against a piloted simulation conducted on the NASA-Ames Vertical Motion Simulator. Seven experimental test pilots completed evaluations in the ADS-33E-PRF Hover Mission Task Element (MTE) for a matrix of nacelle actuator bandwidths, equivalent rise times and control response sensitivities, and longitudinal cyclic control allocations. Evaluated against this task, longitudinal phase delay shows the Level 1 boundary is around 0.4 0.5 s. Accordingly, Level 1 handling qualities were achieved either with a nacelle actuator bandwidth greater than 4 rad/s, or by employing longitudinal cyclic control to augment low bandwidth nacelle actuation.

Investigation of longitudinal control system for a small hydrofoil boat

NASA Technical Reports Server (NTRS)

Phillips, W. H.; Shaughnessy, J. D.

1976-01-01

An analysis of a hydromechanical system for longitudinal control of a small hydrofoil boat is presented. The system incorporates height and acceleration sensors operating flaps on the foils through a mechanical linkage. Effects of some of the system parameters on the stability and response to waves are shown. The results indicate that the system is capable of providing adequate stability, but the response to stern waves at low frequencies is larger than desired.

Traveling through Time: The Forum Guide to Longitudinal Data Systems. Book Two of Four: Planning and Developing an LDS. NFES 2011-804

ERIC Educational Resources Information Center

National Forum on Education Statistics, 2010

2010-01-01

This document, "Book Two of Four: Planning and Developing an LDS", is the second installment of this Forum (National Forum on Education Statistics) series of guides on longitudinal data systems (LDS). This second book in the guide series delves into the planning, implementation, and evaluation phases of a longitudinal data system (LDS)…

Topological solitons as addressable phase bits in a driven laser

NASA Astrophysics Data System (ADS)

Garbin, Bruno; Javaloyes, Julien; Tissoni, Giovanna; Barland, Stéphane

2015-01-01

Optical localized states are usually defined as self-localized bistable packets of light, which exist as independently controllable optical intensity pulses either in the longitudinal or transverse dimension of nonlinear optical systems. Here we demonstrate experimentally and analytically the existence of longitudinal localized states that exist fundamentally in the phase of laser light. These robust and versatile phase bits can be individually nucleated and canceled in an injection-locked semiconductor laser operated in a neuron-like excitable regime and submitted to delayed feedback. The demonstration of their control opens the way to their use as phase information units in next-generation coherent communication systems. We analyse our observations in terms of a generic model, which confirms the topological nature of the phase bits and discloses their formal but profound analogy with Sine-Gordon solitons.

Permeability of twenty-two small diameter hardwoods growing on southern pine sites

Treesearch

E.T. Choong; F.O. Tesoro; F.G. Manwiller

1974-01-01

Gas permeability of hardwoods growing on southern pine sites is significantly affected by moisture content in the longitudinal direction. The ratio of permeability in the transverse to longitudinal directions is from 12,000:1 for post oak to over 1,000,000:1 for other oaks, but it is not affected by moisture. Although variation in longitudinal permeability varies...

permeability of twenty-two small diameter hardwoods growing on southern pine sites

Treesearch

E.T. Choong; F.O. Tesora

1974-01-01

Gas permeability of hardwoods growing on southern pine sites is significantly affected by moisture content in the longitudinal direction. The ratio of permeability in the transverse to longitudinal directions is from 12,000:1 for post oak to over 1,000,000:1 for other oaks, but it is not affected by moisture. Although variation in longitudinal permeability varies...

Bound acoustic modes in the radiation continuum in isotropic layered systems without periodic structures

NASA Astrophysics Data System (ADS)

Maznev, A. A.; Every, A. G.

2018-01-01

We study the existence of guided acoustic modes in layered structures whose phase velocity is higher than that of bulk waves in a solid substrate or an adjacent fluid half space, which belong to the class of bound states in the radiation continuum (BICs). We demonstrate that in contrast to the electromagnetic case, non-symmetry-protected BICs exist in isotropic layered systems without periodic structures. Two systems supporting non-symmetry-protected sagittally polarized BICs have been identified: (i) a supported solid layer yields BICs whose phase velocity is higher than the transverse velocity of the substrate but lower than the longitudinal velocity; (ii) a supported solid layer loaded by a fluid half space supports BICs whose velocity is higher that the bulk velocity of the fluid but lower than acoustic velocities of the substrate. The latter case is a unique example of BICs in the sense that it does not involve an evanescent field in the fluid half space providing the radiation continuum. In either case, BICs are represented by isolated points in the dispersion relations located within "leaky" branches. We show that these BICs are robust with respect to small perturbations of the system parameters. Numerical results are provided for realistic materials combinations. We also show that no BICs exist in all-fluid layered structures, whereas in solid layered structures there are no shear horizontal BICs and no sagittally polarized BICs whose velocity exceeds the longitudinal velocity of the substrate.

Controlled longitudinal emittance blow-up using band-limited phase noise in CERN PSB

NASA Astrophysics Data System (ADS)

Quartullo, D.; Shaposhnikova, E.; Timko, H.

2017-07-01

Controlled longitudinal emittance blow-up (from 1 eVs to 1.4 eVs) for LHC beams in the CERN PS Booster is currently achievied using sinusoidal phase modulation of a dedicated high-harmonic RF system. In 2021, after the LHC injectors upgrade, 3 eVs should be extracted to the PS. Even if the current method may satisfy the new requirements, it relies on low-power level RF improvements. In this paper another method of blow-up was considered, that is the injection of band-limited phase noise in the main RF system (h=1), never tried in PSB but already used in CERN SPS and LHC, under different conditions (longer cycles). This technique, which lowers the peak line density and therefore the impact of intensity effects in the PSB and the PS, can also be complementary to the present method. The longitudinal space charge, dominant in the PSB, causes significant synchrotron frequency shifts with intensity, and its effect should be taken into account. Another complication arises from the interaction of the phase loop with the injected noise, since both act on the RF phase. All these elements were studied in simulations of the PSB cycle with the BLonD code, and the required blow-up was achieved.

Structural, magnetic and magnetoreactance studies in NiFe2-xRxO4 (x = 0, 0.05; R = Y, Yb and Lu)

NASA Astrophysics Data System (ADS)

Ugendar, Kodam; Chunchu, Venkatrao; Rani, G. Neeraja; Markaneyulu, G.

2018-04-01

Structural, magnetic and magnetoreactance (mr) properties of NiFe2-xRxO4 (x = 0, 0.05; R = Y, Yb and Lu) compounds were investigated and the results are discussed and presented in this paper. Rietveld refined X-ray diffraction (XRD) patterns and Raman spectroscopy revealed the cubic inverse spinel phase for all the compounds investigated. The former also identified small amounts of RFeO3 as the secondary phase. Lattice constant values were increased upon partial substitution of Fe3+ by R3+ (R = Y, Yb and Lu). Magnetization measurements revealed that the magnetic moment of R3+ (R = Y, Yb and Lu) substituted compounds decreased compared with NiFe2O4. mr was measured at 3 kHz and 3 MHz both longitudinal (LT) and transverse (TR) configuration. A maximum mr of 54 % was observed in Y3+ substituted NiFe2O4 in TR mode.

Studying the Longitudinal Study. I. Introduction: Do Impromptu Essays Show Changes in Critical Thinking over the Span of College? Cautions and Insights from a Pilot Case Study.

ERIC Educational Resources Information Center

Clark, Francelia

The problematic results of longitudinal studies on college writing indicate the need for multidimensional studies to be able to explore perceptible changes in students' writing. Accordingly a small pilot case study, to explore the promise and the limitations of doing a longitudinal multidimensional study, investigated whether impromptu essays…

Remote sensing of tropospheric turbulence using GPS radio occultation

NASA Astrophysics Data System (ADS)

Shume, Esayas; Ao, Chi

2016-07-01

Radio occultation (RO) measurements are sensitive to the small-scale irregularities in the atmosphere. In this study, we present a new technique to estimate tropospheric turbulence strength (namely, scintillation index) by analyzing RO amplitude fluctuations in impact parameter domain. GPS RO observations from the COSMIC (Constellation Observing System for Meteorology, Ionosphere, and Climate) satellites enabled us to calculate global maps of scintillation measures, revealing the seasonal, latitudinal, and longitudinal characteristics of the turbulent troposphere. Such information are both difficult and expensive to obtain especially over the oceans. To verify our approach, simulation experiments using the multiple phase screen (MPS) method were conducted. The results show that scintillation indices inferred from the MPS simulations are in good agreement with scintillation measures estimated from COSMIC observations.

The characteristic of gap FBG and its application

NASA Astrophysics Data System (ADS)

Yang, Yuanhong; Hu, Jun; Liu, Xuejing; Jin, Wei

2015-07-01

A gap fiber Bragg grating (g-FBG) is fabricated by cutting a uniform FBG in the middle to introduce a small air gap between the two sections. Numerical and experimental investigations show that the g-FBG has the characteristics of both a phase shifted FBG and a Fizeau interferometer. The influence of the air-gap shift longitudinally or transversely with respect to the fiber central axis and temperature to g-FBG's spectrums are investigated with numerical simulation and experiments, and the mathematic models are made. Based on g-FBG's different sensitivity to gap width and temperature, a micro-gap and temperature simultaneous measurement sensor was demonstrated. And a g-FBG based tunable fiber ring laser with a narrow line-width is demonstrated.

Faith Maturity and Mental Well-Being: A Longitudinal Study of Indian American Followers of a Guru Tradition.

PubMed

Pandya, Samta P

2018-05-05

This article is based on a longitudinal study of Indian Americans devoted to a guru tradition, aiming to explore how faith contributes to their mental well-being. Respondent sample size at phase 1 (2003-2004) was 1872 and at phase 2 (2013-2014) was 1764. Two scales were used to measure faith maturity and well-being. Results showed that phase 2 well-being scores of the devotees were higher, influenced by faith maturity and engagement regularity, thereby corroborating the faith-religiosity-well-being link, further reinforced by the structural equation model. Faith emerges as critical variable in working with this cohort and planning interventions towards promoting their well-being.

Dispersivity of Bidisperse Packings of Spheres and Evidence for Distinct Random Structures

NASA Astrophysics Data System (ADS)

Scheven, U. M.

2018-05-01

The intrinsic longitudinal and transverse dispersivity of bidisperse random packings of spheres with size ratio 5 ∶1 was determined by pulsed field gradient nuclear magnetic resonance, in the dilute regime where small spheres occupy between 0% and 5% of the packings' volume. Small spheres plugging pores systematically raise the mechanical transverse and longitudinal dispersivity above that of reference packings of monodisperse spheres. NMR-derived porosities, widths of velocity distributions, and dispersivities reveal distinct states of structural disorder above and below a relative sphere concentration n /N =1 , where n and N are the number densities of small and large spheres.

Linearization of the longitudinal phase space without higher harmonic field

NASA Astrophysics Data System (ADS)

Zeitler, Benno; Floettmann, Klaus; Grüner, Florian

2015-12-01

Accelerator applications like free-electron lasers, time-resolved electron diffraction, and advanced accelerator concepts like plasma acceleration desire bunches of ever shorter longitudinal extent. However, apart from space charge repulsion, the internal bunch structure and its development along the beam line can limit the achievable compression due to nonlinear phase space correlations. In order to improve such a limited longitudinal focus, a correction by properly linearizing the phase space is required. At large scale facilities like Flash at Desy or the European Xfel, a higher harmonic cavity is installed for this purpose. In this paper, another method is described and evaluated: Expanding the beam after the electron source enables a higher order correction of the longitudinal focus by a subsequent accelerating cavity which is operated at the same frequency as the electron gun. The elaboration of this idea presented here is based on a ballistic bunching scheme, but can be extended to bunch compression based on magnetic chicanes. The core of this article is an analytic model describing this approach, which is verified by simulations, predicting possible bunch length below 1 fs at low bunch charge. Minimizing the energy spread down to σE/E <1 0-5 while keeping the bunch long is another interesting possibility, which finds applications, e.g., in time resolved transmission electron microscopy concepts.

Recovering from a stroke: a longitudinal, qualitative study of older Norwegian women.

PubMed

Eilertsen, Grethe; Kirkevold, Marit; Bjørk, Ida Torunn

2010-07-01

To illuminate older women's experiences and the characteristics of the recovery process following a stroke. Patients with stroke face serious challenges related to bodily changes, existential aspects and daily life after stroke. Few qualitative longitudinal studies have examined the recovery process from the perspective of the patient. Knowledge about older women's experiences in coping with life after a stroke is limited. Prospective, longitudinal, case-study design. Six women aged 68-83 suffering from first-time stroke were recruited from two stroke units. Each participant was interviewed in-depth 12-14 times during the first two years post stroke. The interviews addressed how they experienced their body, their self-understanding, daily life and how this had changed over time. Most interviews took place in the participants' homes. Gadamer's philosophical hermeneutics informed the analyses. Post stroke recovery was slow and complex and evolved through four distinct phases. In the first phase (0-2 months post stroke), the participants' main concerns were their bodily changes; in the second phase (2-6 months), activities of daily life; in the third phase (6-12 months), self-understanding and in the fourth phase (12-24 months), going on with life. The transition between phases was gradual. Recovery from stroke evolves over time through four distinct phases, which differ depending on significant experiences and associated meanings. Psychological and social resources are equally critical in the women's process of recovery. The four phases of rehabilitation suggest at what points various concerns require increased therapeutic attention. Psychological and social resources must be vitalised at an early phase similar to bodily resources. This knowledge may assist professionals in offering adequate help throughout the recovery process even beyond the established rehabilitation period. © 2010 Blackwell Publishing Ltd.

A Green's function method for two-dimensional reactive solute transport in a parallel fracture-matrix system

NASA Astrophysics Data System (ADS)

Chen, Kewei; Zhan, Hongbin

2018-06-01

The reactive solute transport in a single fracture bounded by upper and lower matrixes is a classical problem that captures the dominant factors affecting transport behavior beyond pore scale. A parallel fracture-matrix system which considers the interaction among multiple paralleled fractures is an extension to a single fracture-matrix system. The existing analytical or semi-analytical solution for solute transport in a parallel fracture-matrix simplifies the problem to various degrees, such as neglecting the transverse dispersion in the fracture and/or the longitudinal diffusion in the matrix. The difficulty of solving the full two-dimensional (2-D) problem lies in the calculation of the mass exchange between the fracture and matrix. In this study, we propose an innovative Green's function approach to address the 2-D reactive solute transport in a parallel fracture-matrix system. The flux at the interface is calculated numerically. It is found that the transverse dispersion in the fracture can be safely neglected due to the small scale of fracture aperture. However, neglecting the longitudinal matrix diffusion would overestimate the concentration profile near the solute entrance face and underestimate the concentration profile at the far side. The error caused by neglecting the longitudinal matrix diffusion decreases with increasing Peclet number. The longitudinal matrix diffusion does not have obvious influence on the concentration profile in long-term. The developed model is applied to a non-aqueous-phase-liquid (DNAPL) contamination field case in New Haven Arkose of Connecticut in USA to estimate the Trichloroethylene (TCE) behavior over 40 years. The ratio of TCE mass stored in the matrix and the injected TCE mass increases above 90% in less than 10 years.

Elastic Properties across the y→α Volume Collapse in Cerium versus Pressure and Temperature

DOE PAGES

Lipp, M. J.; Jenei, Zs.; Cynn, H.; ...

2017-10-31

Here, the longitudinal and transverse sound speeds, c L and c T, of polycrystalline cerium were measured isothermally vs pressure up to the critical temperature across the iso-structural γ-α volume collapse (VC) phase transition. We deduce values for the adiabatic bulk modulus BS, the shear modulus G = ρc T 2, the Poisson’s ratio ν and the Debye temperature, θ D(p). We find that the elastic constant C 12 is solely responsible for the decrease of B S with pressure towards the VC at RT. With increasing temperature, the lattice contribution ΔS vib(γ→α) to the total entropy change across themore » VC decreases more rapidly to zero than the total entropy itself suggesting that another mechanism, possibly disorder, assists in stabilizing the γ-phase entropically against the α-phase. Also, with increasing temperature, the Poisson’s ratio becomes negative near the VC transition, meaning that cerium metal takes on auxetic characteristics over a small pressure range. At the critical point the Poisson’s ratio ought to be -1, since the isothermal bulk modulus vanishes and the shear modulus remains nonzero.« less

Elastic Properties across the y→α Volume Collapse in Cerium versus Pressure and Temperature

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lipp, M. J.; Jenei, Zs.; Cynn, H.

Here, the longitudinal and transverse sound speeds, c L and c T, of polycrystalline cerium were measured isothermally vs pressure up to the critical temperature across the iso-structural γ-α volume collapse (VC) phase transition. We deduce values for the adiabatic bulk modulus BS, the shear modulus G = ρc T 2, the Poisson’s ratio ν and the Debye temperature, θ D(p). We find that the elastic constant C 12 is solely responsible for the decrease of B S with pressure towards the VC at RT. With increasing temperature, the lattice contribution ΔS vib(γ→α) to the total entropy change across themore » VC decreases more rapidly to zero than the total entropy itself suggesting that another mechanism, possibly disorder, assists in stabilizing the γ-phase entropically against the α-phase. Also, with increasing temperature, the Poisson’s ratio becomes negative near the VC transition, meaning that cerium metal takes on auxetic characteristics over a small pressure range. At the critical point the Poisson’s ratio ought to be -1, since the isothermal bulk modulus vanishes and the shear modulus remains nonzero.« less

Longitudinal changes in cortical thickness in autism and typical development

PubMed Central

Prigge, Molly B. D.; Nielsen, Jared A.; Froehlich, Alyson L.; Abildskov, Tracy J.; Anderson, Jeffrey S.; Fletcher, P. Thomas; Zygmunt, Kristen M.; Travers, Brittany G.; Lange, Nicholas; Alexander, Andrew L.; Bigler, Erin D.; Lainhart, Janet E.

2014-01-01

The natural history of brain growth in autism spectrum disorders remains unclear. Cross-sectional studies have identified regional abnormalities in brain volume and cortical thickness in autism, although substantial discrepancies have been reported. Preliminary longitudinal studies using two time points and small samples have identified specific regional differences in cortical thickness in the disorder. To clarify age-related trajectories of cortical development, we examined longitudinal changes in cortical thickness within a large mixed cross-sectional and longitudinal sample of autistic subjects and age- and gender-matched typically developing controls. Three hundred and forty-five magnetic resonance imaging scans were examined from 97 males with autism (mean age = 16.8 years; range 3–36 years) and 60 males with typical development (mean age = 18 years; range 4–39 years), with an average interscan interval of 2.6 years. FreeSurfer image analysis software was used to parcellate the cortex into 34 regions of interest per hemisphere and to calculate mean cortical thickness for each region. Longitudinal linear mixed effects models were used to further characterize these findings and identify regions with between-group differences in longitudinal age-related trajectories. Using mean age at time of first scan as a reference (15 years), differences were observed in bilateral inferior frontal gyrus, pars opercularis and pars triangularis, right caudal middle frontal and left rostral middle frontal regions, and left frontal pole. However, group differences in cortical thickness varied by developmental stage, and were influenced by IQ. Differences in age-related trajectories emerged in bilateral parietal and occipital regions (postcentral gyrus, cuneus, lingual gyrus, pericalcarine cortex), left frontal regions (pars opercularis, rostral middle frontal and frontal pole), left supramarginal gyrus, and right transverse temporal gyrus, superior parietal lobule, and paracentral, lateral orbitofrontal, and lateral occipital regions. We suggest that abnormal cortical development in autism spectrum disorders undergoes three distinct phases: accelerated expansion in early childhood, accelerated thinning in later childhood and adolescence, and decelerated thinning in early adulthood. Moreover, cortical thickness abnormalities in autism spectrum disorders are region-specific, vary with age, and may remain dynamic well into adulthood. PMID:24755274

Thermodynamics of a dilute XX chain in a field

DOE Office of Scientific and Technical Information (OSTI.GOV)

Timonin, P. N., E-mail: pntim@live.ru

Gapless phases in ground states of low-dimensional quantum spin systems are rather ubiquitous. Their peculiarity is a remarkable sensitivity to external perturbations due to permanent criticality of such phases manifested by a slow (power-low) decay of pair correlations and the divergence of the corresponding susceptibility. A strong influence of various defects on the properties of the system in such a phase can then be expected. Here, we consider the influence of vacancies on the thermodynamics of the simplest quantum model with a gapless phase, the isotropic spin-1/2 XX chain. The existence of the exact solution of this model gives amore » unique opportunity to describe in detail the dramatic effect of dilution on the gapless phase—the appearance of an infinite series of quantum phase transitions resulting from level crossing under the variation of a longitudinal magnetic field. We calculate the jumps in the field dependences of the ground-state longitudinal magnetization, susceptibility, entropy, and specific heat appearing at these transitions and show that they result in a highly nonlinear temperature dependence of these parameters at low T. Also, the effect of enhancement of the magnetization and longitudinal correlations in the dilute chain is established. The changes of the pair spin correlators under dilution are also analyzed. The universality of the mechanism of the quantum transition generation suggests that similar effects of dilution can also be expected in gapless phases of other low-dimensional quantum spin systems.« less

Propagation characteristics of longitudinal-type leaky surface acoustic wave on layered structure consisting of Sc x Al1‑ x N film/LiNbO3 substrate

NASA Astrophysics Data System (ADS)

Suzuki, Masashi; Gomi, Masashi; Kakio, Shoji

2018-07-01

A longitudinal-type leaky surface acoustic wave (LLSAW) has a high phase velocity. Therefore, LLSAW devices are suitable for applications to high-frequency filters. However, the attenuation of LLSAWs is higher than that of other SAW modes. This higher attenuation of LLSAWs, which causes a low Q factor, can be reduced by growing a higher-velocity film on a piezoelectric substrate. On the other hand, K 2 in the layered structure decreases because of the small piezoelectricity in high-velocity films. In this study, LLSAW propagation characteristics on a layered structure consisting of high-piezoelectric ScAlN film/X-cut 36°Y-propagation LiNbO3 were investigated. When a (0^\\circ ,0^\\circ ,0^\\circ ) or (0^\\circ ,90^\\circ ,0^\\circ ) ScAlN film was loaded, the reduction of the attenuation was observed, but K 2 for this layered structure is lower than that of LiNbO3. On the other hand, K 2 for (0^\\circ ,90^\\circ ,90^\\circ ) Sc0.4Al0.6N film/LN is higher than that of LiNbO3.

Biomonitoring of perfluorinated compounds in a drop of blood.

PubMed

Mao, Pan; Wang, Daojing

2015-06-02

Biomonitoring of pollutants and their metabolites and derivatives using biofluids provides new opportunities for spatiotemporal assessment of human risks to environmental exposures. Perfluorinated compounds (PFCs) have been used widely in industry and pose significant environmental concerns due to their stability and bioaccumulation in humans and animals. However, current methods for extraction and measurement of PFCs require relatively large volumes (over one hundred microliters) of blood samples, and therefore, are not suitable for frequent blood sampling and longitudinal biomonitoring of PFCs. We have developed a new microassay, enabled by our silicon microfluidic chip platform, for analyzing PFCs in small volumes (less than five microliters) of blood. Our assay integrates on-chip solid-phase extraction (SPE) with online nanoflow liquid chromatography-electrospray ionization-mass spectrometry (nanoLC-ESI-MS) detection. We demonstrated high sample recovery, excellent interday and intraday accuracy and precision, and a limit of detection down to 50 femtogram of PFCs, in one microliter of human plasma. We validated our assay performance using pooled human plasma and NIST SRM 1950 samples. Our microfluidic chip-based assay may enable frequent longitudinal biomonitoring of PFCs and other environmental toxins using a finger prick of blood, thereby providing new insights into their bioaccumulation, bioavailability, and toxicity.

On the thermal decay of magnetization in the presence of demagnetizing fields and a soft magnetic layer

NASA Astrophysics Data System (ADS)

Wood, R.; Monson, J.; Coughlin, T.

1999-03-01

The presence of a soft magnetic layer adjacent to a magnetic recording medium reduces the demagnetization of both perpendicular and longitudinal recording media. However, for perpendicular media, there is no reduction in the worst case, DC, demagnetizing field and no lessening of the decay. For longitudinal media, the highest demagnetizing fields occur at high densities. The soft layer or keeper can reduce these fields significantly and slow the initial decay. The soft underlayer also induces a small anisotropy field that assists the thermal stability of a perpendicular medium. A similar layer with a longitudinal medium, however, causes a small reduction in thermal stability, but only at low levels of demagnetizing field. For longitudinal recording media the overall effect of the keeper on thermal stability is quite complicated: the initial decay may be delayed significantly (a factor of ten in time) but the final decay to zero may still proceed more rapidly.

Heisenberg spin-1/2 XXZ chain in the presence of electric and magnetic fields

NASA Astrophysics Data System (ADS)

Thakur, Pradeep; Durganandini, P.

2018-02-01

We study the interplay of electric and magnetic order in the one-dimensional Heisenberg spin-1/2 XXZ chain with large Ising anisotropy in the presence of the Dzyaloshinskii-Moriya (DM) interaction and with longitudinal and transverse magnetic fields, interpreting the DM interaction as a coupling between the local electric polarization and an external electric field. We obtain the ground state phase diagram using the density matrix renormalization group method and compute various ground state quantities like the magnetization, staggered magnetization, electric polarization and spin correlation functions, etc. In the presence of both longitudinal and transverse magnetic fields, there are three different phases corresponding to a gapped Néel phase with antiferromagnetic (AF) order, gapped saturated phase, and a critical incommensurate gapless phase. The external electric field modifies the phase boundaries but does not lead to any new phases. Both external magnetic fields and electric fields can be used to tune between the phases. We also show that the transverse magnetic field induces a vector chiral order in the Néel phase (even in the absence of an electric field) which can be interpreted as an electric polarization in a direction parallel to the AF order.

Role of phase matching in pulsed second-harmonic generation: Walk-off and phase-locked twin pulses in negative-index media

NASA Astrophysics Data System (ADS)

Roppo, Vito; Centini, Marco; Sibilia, Concita; Bertolotti, Mario; de Ceglia, Domenico; Scalora, Michael; Akozbek, Neset; Bloemer, Mark J.; Haus, Joseph W.; Kosareva, Olga G.; Kandidov, Valery P.

2007-09-01

The present investigation is concerned with the study of pulsed second-harmonic generation under conditions of phase and group velocity mismatch, and generally low conversion efficiencies and pump intensities. In positive-index, nonmetallic materials, we generally find qualitative agreement with previous reports regarding the presence of a double-peaked second harmonic signal, which comprises a pulse that walks off and propagates at the nominal group velocity one expects at the second-harmonic frequency, and a second pulse that is “captured” and propagates under the pump pulse. We find that the origin of the double-peaked structure resides in a phase-locking mechanism that characterizes not only second-harmonic generation, but also χ(3) processes and third-harmonic generation. The phase-locking mechanism that we describe occurs for arbitrarily small pump intensities, and so it is not a soliton effect, which usually relies on a threshold mechanism, although multicolor solitons display similar phase locking characteristics. Thus, in second harmonic generation a phase-matched component is always generated, even under conditions of material phase mismatch: This component is anomalous, because the material does not allow energy exchange between the pump and the second-harmonic beam. On the other hand, if the material is phase matched, phase locking and phase matching are indistinguishable, and the conversion process becomes efficient. We also report a similar phase-locking phenomenon in negative index materials. A spectral analysis of the pump and the generated signals reveals that the phase-locking phenomenon causes the forward moving, phase-locked second-harmonic pulse to experience the same negative index as the pump pulse, even though the index of refraction at the second-harmonic frequency is positive. Our analysis further shows that the reflected second-harmonic pulse generated at the interface and the forward-moving, phase-locked pulse appear to be part of the same pulse initially generated at the surface, part of which is immediately back-reflected, while the rest becomes trapped and dragged along by the pump pulse. These pulses thus constitute twin pulses generated at the interface, having the same negative wave vector, but propagating in opposite directions. Almost any break of the longitudinal symmetry, even an exceedingly small χ(2) discontinuity, releases the trapped pulse which then propagates in the backward direction. These dynamics are indicative of very rich and intricate interactions that characterize ultrashort pulse propagation phenomena.

Role of phase matching in pulsed second-harmonic generation: Walk-off and phase-locked twin pulses in negative-index media

DOE Office of Scientific and Technical Information (OSTI.GOV)

Roppo, Vito; Centini, Marco; Sibilia, Concita

The present investigation is concerned with the study of pulsed second-harmonic generation under conditions of phase and group velocity mismatch, and generally low conversion efficiencies and pump intensities. In positive-index, nonmetallic materials, we generally find qualitative agreement with previous reports regarding the presence of a double-peaked second harmonic signal, which comprises a pulse that walks off and propagates at the nominal group velocity one expects at the second-harmonic frequency, and a second pulse that is 'captured' and propagates under the pump pulse. We find that the origin of the double-peaked structure resides in a phase-locking mechanism that characterizes not onlymore » second-harmonic generation, but also {chi}{sup (3)} processes and third-harmonic generation. The phase-locking mechanism that we describe occurs for arbitrarily small pump intensities, and so it is not a soliton effect, which usually relies on a threshold mechanism, although multicolor solitons display similar phase locking characteristics. Thus, in second harmonic generation a phase-matched component is always generated, even under conditions of material phase mismatch: This component is anomalous, because the material does not allow energy exchange between the pump and the second-harmonic beam. On the other hand, if the material is phase matched, phase locking and phase matching are indistinguishable, and the conversion process becomes efficient. We also report a similar phase-locking phenomenon in negative index materials. A spectral analysis of the pump and the generated signals reveals that the phase-locking phenomenon causes the forward moving, phase-locked second-harmonic pulse to experience the same negative index as the pump pulse, even though the index of refraction at the second-harmonic frequency is positive. Our analysis further shows that the reflected second-harmonic pulse generated at the interface and the forward-moving, phase-locked pulse appear to be part of the same pulse initially generated at the surface, part of which is immediately back-reflected, while the rest becomes trapped and dragged along by the pump pulse. These pulses thus constitute twin pulses generated at the interface, having the same negative wave vector, but propagating in opposite directions. Almost any break of the longitudinal symmetry, even an exceedingly small {chi}{sup (2)} discontinuity, releases the trapped pulse which then propagates in the backward direction. These dynamics are indicative of very rich and intricate interactions that characterize ultrashort pulse propagation phenomena.« less

Longitudinal waves in carbon nanotubes in the presence of transverse magnetic field and elastic medium

NASA Astrophysics Data System (ADS)

Liu, Hu; Liu, Hua; Yang, Jialing

2017-09-01

In the present paper, the coupling effect of transverse magnetic field and elastic medium on the longitudinal wave propagation along a carbon nanotube (CNT) is studied. Based on the nonlocal elasticity theory and Hamilton's principle, a unified nonlocal rod theory which takes into account the effects of small size scale, lateral inertia and radial deformation is proposed. The existing rod theories including the classic rod theory, the Rayleigh-Love theory and Rayleigh-Bishop theory for macro solids can be treated as the special cases of the present model. A two-parameter foundation model (Pasternak-type model) is used to represent the elastic medium. The influence of transverse magnetic field, Pasternak-type elastic medium and small size scale on the longitudinal wave propagation behavior of the CNT is investigated in detail. It is shown that the influences of lateral inertia and radial deformation cannot be neglected in analyzing the longitudinal wave propagation characteristics of the CNT. The results also show that the elastic medium and the transverse magnetic field will also affect the longitudinal wave dispersion behavior of the CNT significantly. The results obtained in this paper are helpful for understanding the mechanical behaviors of nanostructures embedded in an elastic medium.

Enhancement and inhibition of light tunneling mediated by resonant mode conversion.

PubMed

Kartashov, Yaroslav V; Vysloukh, Victor A; Torner, Lluis

2014-02-15

We show that the rate at which light tunnels between neighboring multimode waveguides can be drastically increased or reduced by the presence of small longitudinal periodic modulations of the waveguide properties that stimulate resonant conversion between the eigenmodes of each waveguide. Such a conversion, available only in multimode guiding structures, leads to periodic power transfer into higher-order modes, whose tails may considerably overlap with neighboring waveguides. As a result, the effective coupling constant for neighboring waveguides may change by several orders of magnitude upon small variations in the longitudinal modulation parameters.

CIR-XL recurring for several years

NASA Astrophysics Data System (ADS)

Dósa, Melinda; Erdös, Géza

2016-04-01

The heliospheric magnetic flux is determined from the radial component of the magnetic field vector measured onboard interplanetary space probes. Earlier Ulysses research has shown remarkable independence of the flux from heliographic latitude. Here we are investigating whether any longitudinal variation exist in the 50 year long OMNI magnetic data set. When determining the heliographic longitude of the plasma source, correction was applied for the solar wind travel time. Significant recurrent enhancements of the magnetic flux was observed during the declining phase of the solar cycles. These flux enhancements are associated with co-rotating interaction regions (CIR) lasting several years. The recurrence period is slightly faster than the Carrington Rotation rate. The same, long lasting recurring features can be observed when plotting the deviation angle of the solar wind velocity vector from the radial direction. However, the deviation angle is small - in order of a few degrees - and cannot account for the observed flux increases. An increase of the magnetic field is clearly caused by the plasma compression associated to CIRs. Comparing interplanetary data with synoptic maps of the coronal magnetic field (PFSS modell) and coronal temperature data of ACE, we came to the possible explanation that these long-term structures are caused by fast speed solar wind originating from coronal holes. This results supports the idea that magnetic field lines from coronal holes spread out and reach to low latitudes as well. The recurrent longitudinal variation of the magnetic flux during the declining phase of the solar cycle has impact on the modulation of cosmic rays as well as on the frequency and intensity of space weather events.

Longitudinal Stability and Control Characteristics at Transonic Speeds of a 1/30-Scale Model of the Republic XF-103 Airplane

NASA Technical Reports Server (NTRS)

Luoma, Arvo A.

1954-01-01

The longitudinal stability and control characteristics of a 1/30-scale model of the Republic XF-103 airplane were investigated in the Langley 8-foot transonic tunnel. The effect of speed brakes located at the end of the fuselage was also investigated. The main part of the investigation was made with internal flow in the model, but some data were obtained with no internal flow. The longitudinal stability and control at transonic-speeds appeared satisfactory. The transonic drag rise was small. The speed brakes had no adverse effects on longitudinal stability.

Total marrow irradiation using Helical TomoTherapy

NASA Astrophysics Data System (ADS)

Garcia-Fernandez, Lourdes Maria

Clinical dose response data of human tumours are limited or restricted to a radiation dose range determined by the level of toxicity to the normal tissues. This is the case for the most common disseminated plasma cell neoplasm, multiple myeloma, where the maximum dose deliverable to the entire bony skeleton using a standard total body irradiation (TBI) technique is limited to about 12 Gy. This study is part of scientific background of a phase I/II dose escalation clinical trial for multiple myeloma using image-guided intensity modulated radiotherapy (IG-IMRT) to deliver high dose to the entire volume of bone marrow with Helical TomoTherapy (HT). This relatively new technology can deliver highly conformal dose distributions to complex target shapes while reducing the dose to critical normal tissues. In this study tools for comparing and predicting the effectiveness of different approaches to total marrow irradiation (TMI) using HT were provided. The expected dose response for plasma cell neoplasms was computed and a radiobiological evaluation of different treatment cohorts in a dose escalating study was performed. Normal tissue complication probability (NTCP) and tumour control probability (TCP) models were applied to an actual TMI treatment plan for a patient and the implications of using different longitudinal field widths were assessed. The optimum dose was ˜39 Gy for which a predicted tumour control of 95% (+/-3%) was obtained, with a predicted 3% (0, 8%) occurrence of radiation pneumonitis. Tissue sparing was seen by using smaller field widths only in the organs of the head. This suggests it would be beneficial to use the small fields in the head only since using small fields for the whole treatment would lead to long treatment times. In TMI it may be necessary to junction two longitudinally adjacent treatment volumes to form a contiguous planning target volume PTV. For instance, this is the case when a different SUP-INF spatial resolution is required or when the PTV length exceeds the bed travel distance. In this work, the dosimetric challenges associated with junctioning longitudinally adjacent PTVs with HT were analyzed and the feasibility of PTV junctioning was demonstrated. The benefits of spatially dividing or splitting the treatment into a few sub-treatments along the longitudinal direction were also investigated.

Student-Development Preparation and Placement: A Longitudinal Study of Graduate Students' and New Professionals' Experiences.

ERIC Educational Resources Information Center

Richmond, Jayne; Sherman, Karen J.

1991-01-01

Examined graduate students' and new professionals' choices and satisfaction with careers, preparation programs, and mentor relationships. Findings from four phases of longitudinal study begun in 1983 with graduate students in student development field suggest that entering students need to be adequately informed about changing career options in…

1982 Maths Investigation: Technical Report. Mt. Druitt Longitudinal Study.

ERIC Educational Resources Information Center

Houghton, Karen; Low, Brian

Aims of this phase of a longitudinal mathematics achievement investigation were to (1) detect individual and group differences in math achievement among a sample of fourth-year children, (2) monitor changes in math skills since a 1981 math investigation, and (3) identify limits of children's understanding of mathematical concepts. (The math test…

A Longitudinal Study of Idiom and Text Comprehension

ERIC Educational Resources Information Center

Levorato, M. Chiara; Roch, Maja; Nesi, Barbara

2007-01-01

The relation between text and idiom comprehension in children with poor text comprehension skills was investigated longitudinally. In the first phase of the study, six-year-old first graders with different levels of text comprehension were compared in an idiom and sentence comprehension task. Text comprehension was shown to be more closely related…

Electrofriction method of manufacturing squirrel cage rotors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hsu, John S.

2005-04-12

A method of making a squirrel cage rotor of copper material for use in AC or DC motors, includes forming a core with longitudinal slots, inserting bars of conductive material in the slots, with ends extending out of opposite ends of the core, and joining the end rings to the bars, wherein the conductive material of either the end rings or the bars is copper. Various methods of joining the end rings to the bars are disclosed including electrofriction welding, current pulse welding and brazing, transient liquid phase joining and casting. Pressure is also applied to the end rings tomore » improve contact and reduce areas of small or uneven contact between the bar ends and the end rings. Rotors made with such methods are also disclosed.« less

Implementing 'self-help friendliness' in German hospitals: a longitudinal study.

PubMed

Trojan, Alf; Nickel, Stefan; Kofahl, Christopher

2016-06-01

In Germany, the term 'self-help friendliness' (SHF) describes a strategy to institutionalize co-operation of healthcare institutions with mutual aid or self-help groups of chronically ill patients. After a short explanation of the SHF concept and its development, we will present findings from a longitudinal study on the implementation of SHF in three German hospitals. Specifically, we wanted to know (i) to what degree SHF had been put into practice after the initial development phase in the pilot hospitals, (ii) whether it was possible to maintain the level of implementation of SHF in the course of at least 1 year and (iii) which opinions exist about the inclusion of SHF criteria in quality management systems. With only minor restrictions, the findings provide support for the usefulness, practicability, sustainability and transferability of SHF. Limitations of our empirical study are the small number of hospitals, the above average motivation of their staff, the small response rate in the staff-survey and the inability to get enough data from members of self-help groups. The research instrument for measuring SHF was adequate and fulfils the most important scientific quality criteria in a German context. We conclude that the implementation of SHF leads to more patient-centredness in healthcare institutions and thus improves satisfaction, self-management, coping and health literacy of patients. SHF is considered as an adequate approach for reorienting healthcare institutions in the sense of the Ottawa Charta, and particularly suitable for health promoting hospitals. © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Generation of longitudinal vibrations in piano strings: From physics to sound synthesis

NASA Astrophysics Data System (ADS)

Bank, Balázs; Sujbert, László

2005-04-01

Longitudinal vibration of piano strings greatly contributes to the distinctive character of low piano notes. In this paper a simplified modal model is developed, which describes the generation of phantom partials and longitudinal free modes jointly. The model is based on the simplification that the coupling from the transverse vibration to the longitudinal polarization is unidirectional. The modal formulation makes it possible to predict the prominent components of longitudinal vibration as a function of transverse modal frequencies. This provides a qualitative insight into the generation of longitudinal vibration, while the model is still capable of explaining the empirical results of earlier works. The semi-quantitative agreement with measurement results implies that the main source of phantom partials is the transverse to longitudinal coupling, while the string termination and the longitudinal to transverse coupling have only small influence. The results suggest that the longitudinal component of the tone can be treated as a quasi-harmonic spectrum with formantlike peaks at the longitudinal modal frequencies. The model is further simplified and applied for the real-time synthesis of piano sound with convincing sonic results. .

Ultrasonic transient bounded-beam propagation in a solid cylinder waveguide embedded in a solid medium.

PubMed

Laguerre, Laurent; Grimault, Anne; Deschamps, Marc

2007-04-01

A semianalytical solution alternative and complementary to modal technique is presented to predict and interpret the ultrasonic pulsed-bounded-beam propagation in a solid cylinder embedded in a solid matrix. The spectral response to an inside axisymmetric velocity source of longitudinal and transversal cylindrical waves is derived from Debye series expansion of the embedded cylinder generalized cylindrical reflection/transmission coefficients. So, the transient guided wave response, synthesized by inverse double Fourier-Bessel transform, is expressed as a combination of the infinite medium contribution, longitudinal, transversal, and coupled longitudinal and transversal waveguide sidewall interactions. Simulated (f, 1/lambdaz) diagrams show the influence of the number of waveguide sidewall interactions to progressively recover dispersion curves. Besides, they show the embedding material filters specific signal portions by concentrating the propagating signal in regions where phase velocity is closer to phase velocity in steel. Then, simulated time waveforms using broadband high-frequency excitation show that signal leading portions exhibit a similar periodical pattern, for both free and embedded waveguides. Debye series-based interpretation shows that double longitudinal/transversal and transversal/longitudinal conversions govern the time waveform leading portion as well as the radiation attenuation in the surrounding cement grout. Finally, a methodology is deduced to minimize the radiation attenuation for the long-range inspection of embedded cylinders.

Nursing students' well-being using the job-demand-control model: A longitudinal study.

PubMed

Tuomi, Jouni; Aimala, Anna-Mari; Žvanut, Boštjan

2016-10-01

Students' well-being is very important both for students and institutions. However, this field lacks longitudinal research, which focuses on the change of nursing students' well-being during their study. In order to asses such changes the four study types according to Job-Demand-Control-Support-model were used: passive, high-strain, low-strain, and active. A longitudinal design was employed: participants were recruited in 2010/2011 (phase I) and at the end of their study in 2012 (phase II). The study was performed in one school of health care in a university of applied sciences in Finland. The final sample consisted of 135 nursing students (BSc) who started their study either in September 2008 or January 2009, and finished in December 2011 or May 2012. The participants responded to the same close-ended questionnaire in both phases. The majority of the participants experienced the study type as low-strain (phase I: 61.5%; phase II: 48.2%). The distribution according to their study type did not change substantially between both phases, although 42.2% of the participants changed their study type. The major changes of study types were from low-strain to others (21.4%), and from other study types to the active one (12.6%). The results indicate that the majority of students do not change their study type and consequentially their well-being during their study, which is in contrast with previous research. Special attention should be put to the identification of students who change their study type to high-strain or remain in it. Copyright © 2016 Elsevier Ltd. All rights reserved.

Influence of longitudinal spin fluctuations on the phase transition features in chiral magnets

NASA Astrophysics Data System (ADS)

Belemuk, A. M.; Stishov, S. M.

2018-04-01

Using the classical Monte Carlo calculations, we investigate the effects of longitudinal spin fluctuations on the helimagnetic transition in a Heisenberg magnet with the Dzyaloshinskii-Moriya interaction. We use variable spin amplitudes in the framework of the spin-lattice Hamiltonian. It is this kind of fluctuations that naturally occur in an itinerant system. We show that the basic features of the helical phase transition are not changed much by the longitudinal spin fluctuations though the transition temperature Tc and the fluctuation hump seen in specific heat at T >Tc is significantly affected. We report thermodynamic and structural effects of these fluctuations. By increasing the system size in the Monte Carlo modeling, we are able to reproduce the ring shape scattering intensity above the helimagnetic transition temperature Tc, which transforms into the spiral spots seen below Tc in the neutron scattering experiments.

Curriculum development of 6for6: Longitudinal research skills program for rural and remote family physicians.

PubMed

McCarthy, Patti; Bethune, Cheri; Fitzgerald, Shari; Graham, Wendy; Asghari, Shabnam; Heeley, Thomas; Godwin, Marshall

2016-02-01

To address barriers challenging the engagement of rural and remote family physicians (RRFPs) in research, Memorial University of Newfoundland in St John's has developed a longitudinal faculty development program (FDP) called 6for6. To establish and evaluate a longitudinal FDP that promotes a foundation of research activity. Program description Informed by a needs assessment in phase 1, phase 2 saw the 6for6 curriculum designed, developed, and implemented to reflect the unique needs of RRFPs. Preliminary evaluations have been conducted and results will be presented after year 1 of the program. The 6for6 FDP has been positively received by participants, and it is evident that they will serve as champions of rural research capacity building. It is anticipated that by April 2017, 18 RRFPs will be equipped with the research and leadership skills required to foster research networks within and outside their communities.

All-solid-state single longitudinal mode MOPA laser system

NASA Astrophysics Data System (ADS)

Zhang, Xiang; Gu, Haidong; Hu, Wenhua; Ren, Shilong

2018-03-01

Side diode pumped electro-optical Q Switching Nd: YAG is demonstrated as master oscillator. F-P etalon and twisted-mode cavity combined configuration is introduced to select longitudinal modes. The seed light experiences a round trip through the two flash pump amplifiers, in this device, the 4f image transmission system and SBS phase conjugate mirror is adopted in order to improved beam quality, by compensating the heat depolarization effect and eliminate wave-front distortion. In the condition of 1 or 5 repetitions of the wavelength at 1064nm, it produces the pulse energy of 300mJ, pulse width of 12ns, and energy instability (RMS) below 3% in single longitudinal mode operation. With a type two-phase matched KTP crystal, 532nm green light is yielded, at 1 Hz repetition rate, the pulse energy of green light is more than 150mJ.

Multiple time scale analysis of pressure oscillations in solid rocket motors

NASA Astrophysics Data System (ADS)

Ahmed, Waqas; Maqsood, Adnan; Riaz, Rizwan

2018-03-01

In this study, acoustic pressure oscillations for single and coupled longitudinal acoustic modes in Solid Rocket Motor (SRM) are investigated using Multiple Time Scales (MTS) method. Two independent time scales are introduced. The oscillations occur on fast time scale whereas the amplitude and phase changes on slow time scale. Hopf bifurcation is employed to investigate the properties of the solution. The supercritical bifurcation phenomenon is observed for linearly unstable system. The amplitude of the oscillations result from equal energy gain and loss rates of longitudinal acoustic modes. The effect of linear instability and frequency of longitudinal modes on amplitude and phase of oscillations are determined for both single and coupled modes. For both cases, the maximum amplitude of oscillations decreases with the frequency of acoustic mode and linear instability of SRM. The comparison of analytical MTS results and numerical simulations demonstrate an excellent agreement.

Band transition and topological interface modes in 1D elastic phononic crystals.

PubMed

Yin, Jianfei; Ruzzene, Massimo; Wen, Jihong; Yu, Dianlong; Cai, Li; Yue, Linfeng

2018-05-01

In this report, we design a one-dimensional elastic phononic crystal (PC) comprised of an Aluminum beam with periodically arranged cross-sections to study the inversion of bulk bands due to the change of topological phases. As the geometric parameters of the unit cell varies, the second bulk band closes and reopens forming a topological transition point. This phenomenon is confirmed for both longitudinal waves and bending waves. By constructing a structural system formed by two PCs with different topological phases, for the first time, we experimentally demonstrate the existence of interface mode within the bulk band gap as a result of topological transition for both longitudinal and bending modes in elastic systems, although for bending modes, additional conditions have to be met in order to have the interface mode due to the dispersive nature of the bending waves in uniform media compared to the longitudinal waves.

Longitudinal design considerations to optimize power to detect variances and covariances among rates of change: Simulation results based on actual longitudinal studies

PubMed Central

Rast, Philippe; Hofer, Scott M.

2014-01-01

We investigated the power to detect variances and covariances in rates of change in the context of existing longitudinal studies using linear bivariate growth curve models. Power was estimated by means of Monte Carlo simulations. Our findings show that typical longitudinal study designs have substantial power to detect both variances and covariances among rates of change in a variety of cognitive, physical functioning, and mental health outcomes. We performed simulations to investigate the interplay among number and spacing of occasions, total duration of the study, effect size, and error variance on power and required sample size. The relation between growth rate reliability (GRR) and effect size to the sample size required to detect power ≥ .80 was non-linear, with rapidly decreasing sample sizes needed as GRR increases. The results presented here stand in contrast to previous simulation results and recommendations (Hertzog, Lindenberger, Ghisletta, & von Oertzen, 2006; Hertzog, von Oertzen, Ghisletta, & Lindenberger, 2008; von Oertzen, Ghisletta, & Lindenberger, 2010), which are limited due to confounds between study length and number of waves, error variance with GCR, and parameter values which are largely out of bounds of actual study values. Power to detect change is generally low in the early phases (i.e. first years) of longitudinal studies but can substantially increase if the design is optimized. We recommend additional assessments, including embedded intensive measurement designs, to improve power in the early phases of long-term longitudinal studies. PMID:24219544

Evaluation of vocal fold vibration with an assessment form for high-speed digital imaging: comparative study between healthy young and elderly subjects.

PubMed

Yamauchi, Akihito; Imagawa, Hiroshi; Yokonishi, Hisayuki; Nito, Takaharu; Yamasoba, Tatsuya; Goto, Takao; Takano, Shingo; Sakakibara, Ken-Ichi; Tayama, Niro

2012-11-01

We conducted a prospective study with a subjective assessment form for high-speed digital imaging (HSDI) to elucidate the features of vocal fold vibrations in vocally healthy subjects and to clarify gender- and age-related differences. Healthy adult volunteers participated in this study. They were divided into young (aged 35 and younger) and elderly (aged 65 and older) groups, and the scores of an assessment form for HSDI characteristics elaborated at our institution were statistically analyzed. Twenty-six young subjects (males: 9, females: 17; mean age: 27 years) and 20 elderly subjects (males: 8, females: 12; mean age: 72 years) were assigned to our study. Posterior gap and posterior-to-anterior longitudinal phase difference were characteristic to young females, whereas in young males, mucosal wave, anterior-to-posterior longitudinal phase difference, and supraglottic hyperactivity were frequent. In elderly males, axis shift, asymmetry, supraglottic hyperactivity, increased mucosal wave, lateral phase difference, and anterior-to-posterior longitudinal phase difference were frequent; and in elderly females, high incidence of lateral phase difference, atrophic change, anterior gap, and asymmetry were observed. The results show that the behaviors of vocal fold vibrations were diverse even in healthy subjects with no vocal complaints or history of laryngeal diseases, and hence, the diversity of vocal fold vibrations in normal subjects must be taken into account in evaluating vocal fold vibrations. Copyright © 2012 The Voice Foundation. Published by Mosby, Inc. All rights reserved.

Mechanism for longitudinal growth of rod-shaped bacteria

NASA Astrophysics Data System (ADS)

Taneja, Swadhin; Levitan, Ben; Rutenberg, Andrew

2013-03-01

The peptidoglycan (PG) cell wall along with MreB proteins are major determinants of shape in rod-shaped bacteria. However the mechanism guiding the growth of this elastic network of cross-linked PG (sacculus) that maintains the integrity and shape of the rod-shaped cell remains elusive. We propose that the known anisotropic elasticity and anisotropic loading, due to the shape and turgor pressure, of the sacculus is sufficient to direct small gaps in the sacculus to elongate around the cell, and that subsequent repair leads to longitudinal growth without radial growth. We computationally show in our anisotropically stressed anisotropic elasticity model small gaps can extend stably in the circumferential direction for the known elasticity of the sacculus. We suggest that MreB patches that normally propagate circumferentially, are associated with these gaps and are steered with this common mechanism. This basic picture is unchanged in Gram positive and Gram negative bacteria. We also show that small changes of elastic properties can in fact lead to bi-stable propagation of gaps, both longitudinal and circumferential, that can explain the bi-stability in patch movement observed in ΔmblΔmreb mutants.

Lamb waves increase sensitivity in nondestructive testing

NASA Technical Reports Server (NTRS)

Di Novi, R.

1967-01-01

Lamb waves improve sensitivity and resolution in the detection of small defects in thin plates and small diameter, thin-walled tubing. This improvement over shear waves applies to both longitudinal and transverse flaws in the specimens.

Cassini ISS Observations of Jupiter: An Exoplanet Perspective

NASA Astrophysics Data System (ADS)

West, Robert A.; Knowles, Benjamin

2017-10-01

Understanding the optical and physical properties of planets in our solar system can guide our approach to the interpretation of observations of exoplanets. Although some work has already been done along these lines, there remain low-hanging fruit. During the Cassini Jupiter encounter, the Imaging Science Subsystem (ISS) obtained an extensive set of images over a large range of phase angles (near-zero to 140 degrees) and in filters from near-UV to near-IR, including three methane bands and nearby continuum. The ISS also obtained images using polarizers. Much later in the mission we also obtained distant images while in orbit around Saturn. Some of these data have already been studied to reveal phase behavior (Dyudina et al., Astrophys. J.822, DOI: 10.3847/0004-637X/822/2/76; Mayorga et al., 2016, Astron. J. 152, DOI: 10.3847/0004-6256/152/6/209). Here we examine rotational modulation to determine wavelength and phase angle dependence, and how these may depend on cloud and haze vertical structure and optical properties. The existence of an optically thin forward-scattering and longitudinally-homogeneous haze overlying photometrically-variable cloud fields tends to suppress rotational modulation as phase angle increases, although in the strong 890-nm methane band cloud vertical structure is important. Cloud particles (non-spherical ammonia ice, mostly) have very small polarization signatures at intermediate phase angles and rotational modulation is not apparent above the noise level of our instrument. Part of this work was performed by the Jet Propulsion Lab, Cal. Inst. Of Technology.

Are Small Schools and Private Schools Better for Adolescents' Emotional Adjustment?

ERIC Educational Resources Information Center

Watt, Toni Terling

2003-01-01

Uses National Longitudinal Study of Adolescent Health 1994 to determine whether adolescents benefit from small and/or private schools. Examines depression, suicide and violent dispositions. Refutes claims that students attending these schools are more emotionally adjusted. Discovers these small and/or private schools may actually be detrimental to…

Improving Mathematics Teacher Education in Germany: Empirical Results from a Longitudinal Evaluation of Innovative Programs

ERIC Educational Resources Information Center

Buchholtz, Nils; Kaiser, Gabriele

2013-01-01

Innovative programs for restructuring the entry phase of mathematics teacher education programs have been implemented at various German universities within the last few years. This article reports about the design and the results of a longitudinal evaluation study of the effectiveness of two of these programs aiming to improve mathematics teacher…

Evaluation of "The First Tee" in Promoting Positive Youth Development: Group Comparisons and Longitudinal Trends

ERIC Educational Resources Information Center

Weiss, Maureen R.; Bolter, Nicole D.; Kipp, Lindsay E.

2016-01-01

Purpose: This manuscript represents the 3rd in a series of articles documenting our longitudinal evaluation of "The First Tee," a physical activity-based youth development program that uses golf as a vehicle for teaching life skills and enhancing developmental outcomes. Previous phases of our project: (a) established initial data-based…

Differences in time to peak carbachol-induced contractions between circular and longitudinal smooth muscles of mouse ileum.

PubMed

Azuma, Yasu-Taka; Samezawa, Nanako; Nishiyama, Kazuhiro; Nakajima, Hidemitsu; Takeuchi, Tadayoshi

2016-01-01

The muscular layer in the GI tract consists of an inner circular muscular layer and an outer longitudinal muscular layer. Acetylcholine (ACh) is the representative neurotransmitter that causes contractions in the gastrointestinal tracts of most animal species. There are many reports of muscarinic receptor-mediated contraction of longitudinal muscles, but few studies discuss circular muscles. The present study detailed the contractile response in the circular smooth muscles of the mouse ileum. We used small muscle strips (0.2 mm × 1 mm) and large muscle strips (4 × 4 mm) isolated from the circular and longitudinal muscle layers of the mouse ileum to compare contraction responses in circular and longitudinal smooth muscles. The time to peak contractile responses to carbamylcholine (CCh) were later in the small muscle strips (0.2 × 1 mm) of circular muscle (5.7 min) than longitudinal muscles (0.4 min). The time to peak contractile responses to CCh in the large muscle strips (4 × 4 mm) were also later in the circular muscle (3.1 min) than the longitudinal muscle (1.4 min). Furthermore, a muscarinic M2 receptor antagonist and gap junction inhibitor significantly delayed the time to peak contraction of the large muscle strips (4 × 4 mm) from the circular muscular layer. Our findings indicate that muscarinic M2 receptors in the circular muscular layer of mouse ileum exert a previously undocumented function in gut motility via the regulation of gap junctions.

Missing Data in Clinical Studies: Issues and Methods

PubMed Central

Ibrahim, Joseph G.; Chu, Haitao; Chen, Ming-Hui

2012-01-01

Missing data are a prevailing problem in any type of data analyses. A participant variable is considered missing if the value of the variable (outcome or covariate) for the participant is not observed. In this article, various issues in analyzing studies with missing data are discussed. Particularly, we focus on missing response and/or covariate data for studies with discrete, continuous, or time-to-event end points in which generalized linear models, models for longitudinal data such as generalized linear mixed effects models, or Cox regression models are used. We discuss various classifications of missing data that may arise in a study and demonstrate in several situations that the commonly used method of throwing out all participants with any missing data may lead to incorrect results and conclusions. The methods described are applied to data from an Eastern Cooperative Oncology Group phase II clinical trial of liver cancer and a phase III clinical trial of advanced non–small-cell lung cancer. Although the main area of application discussed here is cancer, the issues and methods we discuss apply to any type of study. PMID:22649133

Effect of geometric nonlinearity on acoustic modulation

NASA Astrophysics Data System (ADS)

Warnemuende, Kraig; Wu, Hwai-Chung

2005-05-01

Non-linear nondestructive testing is different from linear acoustic in that it correlates the presence and characteristics of a defect with acoustical signals whose frequencies differ from the frequencies of the emitted probe signal. The difference in frequencies between the probe signal and the resulting frequencies is due to a nonlinear transformation of the probe signal as it passes through a defect. Under acoustic interrogation due to longitudinal waves, as the compression phase passes the defect the two sides of the interface are in direct contact and the contact area increases. Similarly, the tensile phase passes through the defect, the two sides separate and the contact area decreases, thereby modulating the signal amplitude. The contact area depends on the roughness of the surface and on the magnitude of the cohesive forces that arise from the small crack openings. Such cohesive forces may be attributed to aggregate interlock (in plain concrete), fiber bridging (in fiber reinforced concrete) or both. In this paper, the frequency shifts of the probe elastic wave will be analytically related to the roughness and varying cohesive forces of the crack-like defect.

The Effects of Magnetic-field Geometry on Longitudinal Oscillaitons of Solar Prominences

NASA Technical Reports Server (NTRS)

Luna, M.; Diaz, A. J.; Karpen, J.

2013-01-01

We investigate the influence of the geometry of the solar filament magnetic structure on the large-amplitude longitudinal oscillations. A representative filament flux tube is modeled as composed of a cool thread centered in a dipped part with hot coronal regions on either side.We have found the normal modes of the system and establish that the observed longitudinal oscillations are well described with the fundamental mode. For small and intermediate curvature radii and moderate to large density contrast between the prominence and the corona, the main restoring force is the solar gravity. In this full wave description of the oscillation a simple expression for the oscillation frequencies is derived in which the pressure-driven term introduces a small correction. We have also found that the normal modes are almost independent of the geometry of the hot regions of the tube. We conclude that observed large-amplitude longitudinal oscillations are driven by the projected gravity along the flux tubes and are strongly influenced by the curvature of the dips of the magnetic field in which the threads reside.

Seismicity Controlled by a Frictional Afterslip During a Small-Magnitude Seismic Sequence (ML < 5) on the Chihshang Fault, Taiwan

NASA Astrophysics Data System (ADS)

Canitano, Alexandre; Godano, Maxime; Hsu, Ya-Ju; Lee, Hsin-Ming; Linde, Alan T.; Sacks, Selwyn

2018-02-01

We report evidence for frictional afterslip at shallow depths (about 5 to 7 km) during a small-magnitude seismic sequence (with ML<5) along the Chihshang Fault, a main active structure of the Longitudinal Valley, in southeast Taiwan. The afterslip, which was recorded by a nearby borehole dilatometer, lasted about a month with a cumulative geodetic moment magnitude of 4.8 ± 0.2. The afterslip comprised two stages and controlled the aftershock sequence. The first postseismic stage, which followed a ML 4.6 earthquake, lasted about 6 h and mostly controlled the ruptures of neighboring asperities (e.g., multiplets) near the hypocenter. Then, a 4 week duration large afterslip event following a ML 4.9 earthquake controlled the rate of aftershocks during its first 2 days through brittle creep. The study presents a rare case of simultaneous seismological and geodetic observations for afterslip following earthquakes with magnitude lower than 5. Furthermore, the geodetic moment of the postseismic phase is at least equivalent to the coseismic moment of the sequence.

The quantitative impact of the mesopore size on the mass transfer mechanism of the new 1.9μm fully porous Titan-C18 particles. I: analysis of small molecules.

PubMed

Gritti, Fabrice; Guiochon, Georges

2015-03-06

Previous data have shown that could deliver a minimum reduced plate height as small as 1.7. Additionally, the reduction of the mesopore size after C18 derivatization and the subsequent restriction for sample diffusivity across the Titan-C18 particles were found responsible for the unusually small value of the experimental optimum reduced velocity (5 versus 10 for conventional particles) and for the large values of the average reduced solid-liquid mass transfer resistance coefficients (0.032 versus 0.016) measured for a series of seven n-alkanophenones. The improvements in column efficiency made by increasing the average mesopore size of the Titan silica from 80 to 120Å are investigated from a quantitative viewpoint based on the accurate measurements of the reduced coefficients (longitudinal diffusion, trans-particle mass transfer resistance, and eddy diffusion) and of the intra-particle diffusivity, pore, and surface diffusion for the same series of n-alkanophenone compounds. The experimental results reveal an increase (from 0% to 30%) of the longitudinal diffusion coefficients for the same sample concentration distribution (from 0.25 to 4) between the particle volume and the external volume of the column, a 40% increase of the intra-particle diffusivity for the same sample distribution (from 1 to 7) between the particle skeleton volume and the bulk phase, and a 15-30% decrease of the solid-liquid mass transfer coefficient for the n-alkanophenone compounds. Pore and surface diffusion are increased by 60% and 20%, respectively. The eddy dispersion term and the maximum column efficiency (295000plates/m) remain virtually unchanged. The rate of increase of the total plate height with increasing the chromatographic speed is reduced by 20% and it is mostly controlled (75% and 70% for 80 and 120Å pore size) by the flow rate dependence of the eddy dispersion term. Copyright © 2015 Elsevier B.V. All rights reserved.

Notes on phase transitions and the role of spin fluctuations

NASA Astrophysics Data System (ADS)

Stishov, S. M.

2016-09-01

The physical properties of two chiral systems with localized and delocalized magnetic moments, {\\text{Cu}}2{\\text{OSeO}}3 and MnSi, are reviewed. It is concluded that the longitudinal fluctuations of magnetic moments have no strong effect on the qualitative picture of phase transitions and the magnetic phase diagrams of chiral systems.

Presymptomatic and longitudinal neuroimaging in neurodegeneration--from snapshots to motion picture: a systematic review.

PubMed

Schuster, Christina; Elamin, Marwa; Hardiman, Orla; Bede, Peter

2015-10-01

Recent quantitative neuroimaging studies have been successful in capturing phenotype and genotype-specific changes in dementia syndromes, amyotrophic lateral sclerosis, Parkinson's disease and other neurodegenerative conditions. However, the majority of imaging studies are cross-sectional, despite the obvious superiority of longitudinal study designs in characterising disease trajectories, response to therapy, progression rates and evaluating the presymptomatic phase of neurodegenerative conditions. The aim of this work is to perform a systematic review of longitudinal imaging initiatives in neurodegeneration focusing on methodology, optimal statistical models, follow-up intervals, attrition rates, primary study outcomes and presymptomatic studies. Longitudinal imaging studies were identified from 'PubMed' and reviewed from 1990 to 2014. The search terms 'longitudinal', 'MRI', 'presymptomatic' and 'imaging' were utilised in combination with one of the following degenerative conditions; Alzheimer's disease, amyotrophic lateral sclerosis/motor neuron disease, frontotemporal dementia, Huntington's disease, multiple sclerosis, Parkinson's disease, ataxia, HIV, alcohol abuse/dependence. A total of 423 longitudinal imaging papers and 103 genotype-based presymptomatic studies were identified and systematically reviewed. Imaging techniques, follow-up intervals and attrition rates showed significant variation depending on the primary diagnosis. Commonly used statistical models included analysis of annualised percentage change, mixed and random effect models, and non-linear cumulative models with acceleration-deceleration components. Although longitudinal imaging studies have the potential to provide crucial insights into the presymptomatic phase and natural trajectory of neurodegenerative processes a standardised design is required to enable meaningful data interpretation. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

Assessing corporate project impacts in changeable contexts: A human rights perspective

DOE Office of Scientific and Technical Information (OSTI.GOV)

Salcito, Kendyl, E-mail: kendyl.salcito@unibas.ch; University of Basel, P.O. Box, CH-4003 Basel; NomoGaia, 1900 Wazee Street, Suite 303, Denver, CO 80202

Project-level impact assessment was originally conceived as a snapshot taken in advance of project implementation, contrasting current conditions with a likely future scenario involving a variety of predicted impacts. Current best practice guidance has encouraged a shift towards longitudinal assessments from the pre-project stage through the implementation and operating phases. Experience and study show, however, that assessment of infrastructure-intensive projects rarely endures past the project's construction phase. Negative consequences for environmental, social and health outcomes have been documented. Such consequences clarify the pressing need for longitudinal assessment in each of these domains, with human rights impact assessment (HRIA) as anmore » umbrella over, and critical augmentation of, environmental, social and health assessments. Project impacts on human rights are more closely linked to political, economic and other factors beyond immediate effects of a company's policy and action throughout the project lifecycle. Delineating these processes requires an adequate framework, with strategies for collecting longitudinal data, protocols that provide core information for impact assessment and guidance for adaptive mitigation strategies as project-related effects change over time. This article presents general principles for the design and implementation of sustained, longitudinal HRIA, based on experience assessing and responding to human rights impact in a uranium mining project in Malawi. The case study demonstrates the value of longitudinal assessment both for limiting corporate risk and improving human welfare. - Graphical abstract: Assessing changes in human rights condition as affected by both project and context, over time. - Highlights: • Corporate capital projects affect human rights in myriad ways. • Ongoing, longitudinal impact assessment techniques are needed. • We present an approach for conducting longitudinal human rights impact assessment. • Our methodology allows distinguishing corporate impacts from contextual changes. • Promptly observing context changes and impacts enables companies to react nimbly.« less

Improving the Rank Precision of Population Health Measures for Small Areas with Longitudinal and Joint Outcome Models

PubMed Central

Athens, Jessica K.; Remington, Patrick L.; Gangnon, Ronald E.

2015-01-01

Objectives The University of Wisconsin Population Health Institute has published the County Health Rankings since 2010. These rankings use population-based data to highlight health outcomes and the multiple determinants of these outcomes and to encourage in-depth health assessment for all United States counties. A significant methodological limitation, however, is the uncertainty of rank estimates, particularly for small counties. To address this challenge, we explore the use of longitudinal and pooled outcome data in hierarchical Bayesian models to generate county ranks with greater precision. Methods In our models we used pooled outcome data for three measure groups: (1) Poor physical and poor mental health days; (2) percent of births with low birth weight and fair or poor health prevalence; and (3) age-specific mortality rates for nine age groups. We used the fixed and random effects components of these models to generate posterior samples of rates for each measure. We also used time-series data in longitudinal random effects models for age-specific mortality. Based on the posterior samples from these models, we estimate ranks and rank quartiles for each measure, as well as the probability of a county ranking in its assigned quartile. Rank quartile probabilities for univariate, joint outcome, and/or longitudinal models were compared to assess improvements in rank precision. Results The joint outcome model for poor physical and poor mental health days resulted in improved rank precision, as did the longitudinal model for age-specific mortality rates. Rank precision for low birth weight births and fair/poor health prevalence based on the univariate and joint outcome models were equivalent. Conclusion Incorporating longitudinal or pooled outcome data may improve rank certainty, depending on characteristics of the measures selected. For measures with different determinants, joint modeling neither improved nor degraded rank precision. This approach suggests a simple way to use existing information to improve the precision of small-area measures of population health. PMID:26098858

Beam shaping to improve the free-electron laser performance at the Linac Coherent Light Source

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ding, Y.; Bane, K. L. F.; Colocho, W.

2016-10-27

A new operating mode has been developed for the Linac Coherent Light Source (LCLS) in which we shape the longitudinal phase space of the electron beam. This mode of operation is realized using a horizontal collimator located in the middle of the first bunch compressor to truncate the head and tail of the beam. With this method, the electron beam longitudinal phase space and current profile are reshaped, and improvement in lasing performance can be realized. As a result, we present experimental studies at the LCLS of the beam shaping effects on the free-electron laser performance.

Spontaneous magnetic order in complex materials: Role of longitudinal spin-orbit interactions

NASA Astrophysics Data System (ADS)

Chakraborty, Subrata; Vijay, Amrendra

2017-06-01

We show that the longitudinal spin-orbit interactions (SOI) critically determine the fate of spontaneous magnetic order (SMO) in complex materials. To study the magnetic response of interacting electrons constituting the material, we implement an extension of the Hubbard model that faithfully accounts for the SOI. Next, we use the double-time Green functions of quantum statistical mechanics to obtain the spontaneous magnetization, Msp , and thence ascertain the possibility of SMO. For materials with quenched SOI, in an arbitrary dimension, Msp vanishes at finite temperatures, implying the presence of the disordered (paramagnetic) phase. This is consistent with and goes beyond the Bogolyubov's inequality based analysis in one and two dimensions. In the presence of longitudinal SOI, Msp , for materials in an arbitrary dimension, remains non-zero at finite temperatures, which indicates the existence of the ordered (ferromagnetic) phase. As a plausible experimental evidence of the present SOI-based phenomenology, we discuss, inter alia, a recent experimental study on Y4Mn1-xGa12-yGey, an intermetallic compound, which exhibits a magnetic phase transition (paramagnetic to ferromagnetic) upon tuning the fraction of Ge atoms and thence the vacancies of the magnetic centers in this system. The availability of Ge atoms to form a direct chemical bond with octahedral Mn in this material appears to quench the SOI and, as a consequence, favours the formation of the disordered (paramagnetic) phase.

Field-aligned currents' scale analysis performed with the Swarm constellation

NASA Astrophysics Data System (ADS)

Lühr, Hermann; Park, Jaeheung; Gjerloev, Jesper W.; Rauberg, Jan; Michaelis, Ingo; Merayo, Jose M. G.; Brauer, Peter

2015-01-01

We present a statistical study of the temporal- and spatial-scale characteristics of different field-aligned current (FAC) types derived with the Swarm satellite formation. We divide FACs into two classes: small-scale, up to some 10 km, which are carried predominantly by kinetic Alfvén waves, and large-scale FACs with sizes of more than 150 km. For determining temporal variability we consider measurements at the same point, the orbital crossovers near the poles, but at different times. From correlation analysis we obtain a persistent period of small-scale FACs of order 10 s, while large-scale FACs can be regarded stationary for more than 60 s. For the first time we investigate the longitudinal scales. Large-scale FACs are different on dayside and nightside. On the nightside the longitudinal extension is on average 4 times the latitudinal width, while on the dayside, particularly in the cusp region, latitudinal and longitudinal scales are comparable.

Conformational variability of the stationary phase survival protein E from Xylella fastidiosa revealed by X-ray crystallography, small-angle X-ray scattering studies, and normal mode analysis.

PubMed

Machado, Agnes Thiane Pereira; Fonseca, Emanuella Maria Barreto; Reis, Marcelo Augusto Dos; Saraiva, Antonio Marcos; Santos, Clelton Aparecido Dos; de Toledo, Marcelo Augusto Szymanski; Polikarpov, Igor; de Souza, Anete Pereira; Aparicio, Ricardo; Iulek, Jorge

2017-10-01

Xylella fastidiosa is a xylem-limited bacterium that infects a wide variety of plants. Stationary phase survival protein E is classified as a nucleotidase, which is expressed when bacterial cells are in the stationary growth phase and subjected to environmental stresses. Here, we report four refined X-ray structures of this protein from X. fastidiosa in four different crystal forms in the presence and/or absence of the substrate 3'-AMP. In all chains, the conserved loop verified in family members assumes a closed conformation in either condition. Therefore, the enzymatic mechanism for the target protein might be different of its homologs. Two crystal forms exhibit two monomers whereas the other two show four monomers in the asymmetric unit. While the biological unit has been characterized as a tetramer, differences of their sizes and symmetry are remarkable. Four conformers identified by Small-Angle X-ray Scattering (SAXS) in a ligand-free solution are related to the low frequency normal modes of the crystallographic structures associated with rigid body-like protomer arrangements responsible for the longitudinal and symmetric adjustments between tetramers. When the substrate is present in solution, only two conformers are selected. The most prominent conformer for each case is associated to a normal mode able to elongate the protein by moving apart two dimers. To our knowledge, this work was the first investigation based on the normal modes that analyzed the quaternary structure variability for an enzyme of the SurE family followed by crystallography and SAXS validation. The combined results raise new directions to study allosteric features of XfSurE protein. © 2017 Wiley Periodicals, Inc.

Property evaluations and application for separation of small molecules of a nanodiamond-polymer composite monolithic column.

PubMed

Wang, Fengqing; Wei, Aile; Wang, Xixi; Liu, Haiyan; Bai, Ligai; Yan, Hongyuan

2016-07-01

A nanodiamond-polymer composite monolithic column was first prepared successfully with modified nanodiamond (ND) as monomer, ethylene glycol dimethacrylate (EDMA) as cross-linker, 1-dodecanol as porogenic agent and benzoyl peroxide/dimethylacetamide (BPO/DMA) as initiator at 35°C for 2.5h. There was a sharp increase of specific surface area with ND added about 22 times from 0mg (3.90m(2)/g) to 7mg (81.2m(2)/g) determined with BET. Characterizations including scanning electron microscopy (SEM), fourier-transform infrared spectra (FIRT) and mercury intrusion porosimetry (MIP) were used to determine the microstructure, group composition, pore size distribution (≃1.56μm) and porosity (≃0.7484μm) of the monolith. An excellent column stability was confirmed by permeability (1.258x10(-10)cm(2)) and good linearity (R(2)=0.998) corresponding to backpressures measured at different flow rates. The highest swelling ability of the composite was about (5%) and classical RPLC of the column obtained occurred with the acetonitrile concentration increasing from 20% to 85% in the mobile phase, above which another retention model of normal-phase chromatography appeared. The items of the eddy dispersion and the absorption-release kinetics were the decisional factors of the composite column compared with the factors of longitudinal diffusion, and the skeleton-eluent mass transfer resistance due to the finite diffusivity. Good separation of neutral and basic small molecules was obtained (24,350 plates/m for neutral molecules and 22,300 plates/m for basic ones) with the hydrophobicity retention mechanism, but not for the acidic ones except to regulate the pH of the mobile phase. Copyright © 2016 Elsevier B.V. All rights reserved.

Phase Space Exchange in Thick Wedge Absorbers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Neuffer, David

The problem of phase space exchange in wedge absorbers with ionization cooling is discussed. The wedge absorber exchanges transverse and longitudinal phase space by introducing a position-dependent energy loss. In this paper we note that the wedges used with ionization cooling are relatively thick, so that single wedges cause relatively large changes in beam phase space. Calculation methods adapted to such “thick wedge” cases are presented, and beam phase-space transformations through such wedges are discussed.

Determinants of exercise among children. II. A longitudinal analysis.

PubMed

DiLorenzo, T M; Stucky-Ropp, R C; Vander Wal, J S; Gotham, H J

1998-01-01

Research has demonstrated that physical activity serves an important preventive function against the development of cardiovascular disease. The recognition that U.S. children are often sedentary, coupled with the observation that physical activity habits tend to persist into adulthood, has prompted the investigation of exercise determinants consistent with social learning theory. The purposes of the present study were to identify social learning variables relevant to children's exercise and to explore the longitudinal predictive value of the determinants. Data were collected from 111 families (N = 54 girls, N = 57 boys) who were interviewed in both Phase 1 (fifth and sixth grades) and Phase 2 (eight and ninth grades) of this study. Data from mothers (N = 111) were collected during both phases; data from 80 fathers were collected at Phase 2 only. The results of simultaneous stepwise regression analyses indicated that child's enjoyment of physical activity was the only consistent predictor of physical activity during Phase 1. At Phase 2, child's exercise knowledge, mother's physical activity, and child's and mother's friend modeling/support emerged as predictors for girls. For boys, child's self-efficacy for physical activity, exercise knowledge, parental modeling, and interest in sports media were important. Longitudinally, mother's self-efficacy, barriers to exercise, enjoyment of physical activity, and child's self-efficacy for physical activity were important for girls. Only child's exercise knowledge predicted boys' physical activity. The addition of information from fathers nearly doubled the explanatory power of the predictors for both genders. Socialization in the family unit exerts a tremendous influence on health-related behaviors such as exercise. The relative importance of determinants seems to differ for girls and boys and the pattern of these determinants appears to change over time.

Probing strong electroweak symmetry breaking dynamics through quantum interferometry at the LHC

DOE PAGES

Murayama, Hitoshi; Rentala, Vikram; Shu, Jing

2015-12-07

Here, we present a new probe of strongly coupled electroweak symmetry breaking at the 14 TeV LHC by measuring a phase shift in the event distribution of the decay azimuthal angles in massive gauge boson scattering. One generically expects a large phase shift in the longitudinal gauge boson scattering amplitude due to the presence of broad resonances. This phase shift is observable as an interference effect between the strongly interacting longitudinal modes and the transverse modes of the gauge bosons. We find that even very broad resonances of masses up to 900 GeV can be probed at 3σ significance withmore » a 3000 fb -1 run of the LHC by using this technique. We also present the estimated reach for a future 50 TeV proton-proton collider.« less

A Study of Ontogenetic and Generational Change in Adolescent Personality by Means of Multivariate Longitudinal Sequences: Phase II. Final Report.

ERIC Educational Resources Information Center

Nesselroade, John R.; Baltes, Paul B.

Assessment of the relationship between ontogenetic (individual) and generational (historical) change in adolescent personality development was the focus of this study. The total sample included 1000 male and female adolescents (ages 13-18) randomly drawn from 32 public school systems in West Virginia following a design using longitudinal sequences…

An Examination of the Relationship among High School Size, Social Capital, and Adolescents' Mathematics Achievement

ERIC Educational Resources Information Center

Carolan, Brian V.

2012-01-01

In an effort to enhance both adolescents' social capital and increase achievement, public school districts across the United States have created small high schools. Using data derived from a longitudinal and nationally representative study of U.S. high school students, the Educational Longitudinal Study of 2002, results show that when adolescents'…

Code-Switching and Gender: A Longitudinal Study of Spanish/English Speaking Fraternal Boy-Girl Twins

ERIC Educational Resources Information Center

Robinson, Colin

2015-01-01

Researchers from Jean Piaget (1932) to Sehlauoi (2008) have utilized small case studies to intensively examine naturally occurring child language production in the home environment. This qualitative, 5-year longitudinal, five-year case study continues the focus of previous research on child bilingualism and code-switching; however, it aims to…

Chief Characteristics and Advantages of Tailless Airplanes

NASA Technical Reports Server (NTRS)

Dufaure De Lajarte, A

1936-01-01

This study will be concerned with the critical examination of two main questions, mainly, susceptibility of centering and more generally, the conditions of static stability, longitudinal equilibrium, and the question of dynamic stability, or at least the damping of longitudinal vibrations about a position of equilibrium that may result from a small variation in the angle of attack.

Manifestations of geometric phases in a proton electric-dipole-moment experiment in an all-electric storage ring

NASA Astrophysics Data System (ADS)

Silenko, Alexander J.

2017-12-01

We consider a proton electric-dipole-moment experiment in an all-electric storage ring when the spin is frozen and local longitudinal and vertical electric fields alternate. In this experiment, the geometric (Berry) phases are very important. Due to the these phases, the spin rotates about the radial axis. The corresponding systematic error is rather important while it can be canceled with clockwise and counterclockwise beams. The geometric phases also lead to the spin rotation about the radial axis. This effect can be canceled with clockwise and counterclockwise beams as well. The sign of the azimuthal component of the angular velocity of the spin precession depends on the starting point where the spin orientation is perfect. The radial component of this quantity keeps its value and sign for each starting point. When the longitudinal and vertical electric fields are joined in the same sections without any alternation, the systematic error due to the geometric phases does not appear but another systematic effect of the spin rotation about the azimuthal axis takes place. It has opposite signs for clockwise and counterclockwise beams.

Coupled pendula chains under parametric PT-symmetric driving force

NASA Astrophysics Data System (ADS)

Destyl, E.; Nuiro, S. P.; Pelinovsky, D. E.; Poullet, P.

2017-12-01

We consider a chain of coupled pendula pairs, where each pendulum is connected to the nearest neighbors in the longitudinal and transverse directions. The common strings in each pair are modulated periodically by an external force. In the limit of small coupling and near the 1 : 2 parametric resonance, we derive a novel system of coupled PT-symmetric discrete nonlinear Schrödinger equations, which has Hamiltonian symmetry but has no phase invariance. By using the conserved energy, we find the parameter range for the linear and nonlinear stability of the zero equilibrium. Numerical experiments illustrate how destabilization of the zero equilibrium takes place when the stability constraints are not satisfied. The central pendulum excites nearest pendula and this process continues until a dynamical equilibrium is reached where each pendulum in the chain oscillates at a finite amplitude.

Longitudinal changes in cortical thickness in autism and typical development.

PubMed

Zielinski, Brandon A; Prigge, Molly B D; Nielsen, Jared A; Froehlich, Alyson L; Abildskov, Tracy J; Anderson, Jeffrey S; Fletcher, P Thomas; Zygmunt, Kristen M; Travers, Brittany G; Lange, Nicholas; Alexander, Andrew L; Bigler, Erin D; Lainhart, Janet E

2014-06-01

The natural history of brain growth in autism spectrum disorders remains unclear. Cross-sectional studies have identified regional abnormalities in brain volume and cortical thickness in autism, although substantial discrepancies have been reported. Preliminary longitudinal studies using two time points and small samples have identified specific regional differences in cortical thickness in the disorder. To clarify age-related trajectories of cortical development, we examined longitudinal changes in cortical thickness within a large mixed cross-sectional and longitudinal sample of autistic subjects and age- and gender-matched typically developing controls. Three hundred and forty-five magnetic resonance imaging scans were examined from 97 males with autism (mean age = 16.8 years; range 3-36 years) and 60 males with typical development (mean age = 18 years; range 4-39 years), with an average interscan interval of 2.6 years. FreeSurfer image analysis software was used to parcellate the cortex into 34 regions of interest per hemisphere and to calculate mean cortical thickness for each region. Longitudinal linear mixed effects models were used to further characterize these findings and identify regions with between-group differences in longitudinal age-related trajectories. Using mean age at time of first scan as a reference (15 years), differences were observed in bilateral inferior frontal gyrus, pars opercularis and pars triangularis, right caudal middle frontal and left rostral middle frontal regions, and left frontal pole. However, group differences in cortical thickness varied by developmental stage, and were influenced by IQ. Differences in age-related trajectories emerged in bilateral parietal and occipital regions (postcentral gyrus, cuneus, lingual gyrus, pericalcarine cortex), left frontal regions (pars opercularis, rostral middle frontal and frontal pole), left supramarginal gyrus, and right transverse temporal gyrus, superior parietal lobule, and paracentral, lateral orbitofrontal, and lateral occipital regions. We suggest that abnormal cortical development in autism spectrum disorders undergoes three distinct phases: accelerated expansion in early childhood, accelerated thinning in later childhood and adolescence, and decelerated thinning in early adulthood. Moreover, cortical thickness abnormalities in autism spectrum disorders are region-specific, vary with age, and may remain dynamic well into adulthood. © The Author (2014). Published by Oxford University Press on behalf of the Guarantors of Brain. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Simulation of emission and propagation of coherent synchrotron radiation wave fronts using the methods of wave optics

NASA Astrophysics Data System (ADS)

Chubar, O.

2006-09-01

The paper describes methods of efficient calculation of spontaneous synchrotron radiation (SR) by relativistic electrons in storage rings, and propagation of this radiation through optical elements and drift spaces of beamlines, using the principles of wave optics. In addition to the SR from one electron, incoherent and coherent synchrotron radiation (CSR) emitted by electron bunches is treated. CPU-efficient CSR calculation method taking into account 6D phase space distribution of electrons in a bunch is proposed. The properties of CSR emitted by electron bunches with small longitudinal and large transverse size are studied numerically (such situation can be realized in storage rings e.g. by transverse deflection of the electron bunches in special RF cavities). It is shown that if the transverse size of a bunch is much larger than the diffraction limit for single-electron SR at a given wavelength - it affects the angular distribution of the CSR at this wavelength and reduces the coherent flux. Nevertheless, for transverse bunch dimensions up to several millimeters and the longitudinal bunch size smaller than hundred micrometers, the resulting CSR flux in the far infrared spectral range is still many orders of magnitude higher than the flux of incoherent SR.

Revealing the mechanism of passive transport in lipid bilayers via phonon-mediated nanometre-scale density fluctuations

DOE PAGES

Zhernenkov, Mikhail; Bolmatov, Dima; Soloviov, Dmitry; ...

2016-05-12

We report the high resolution inelastic x-ray study of the in-plane phonon excitations in dipalmitoyl phosphatidylcholine (DPPC) above and below main transition temperature. In the L β' gel phase, we observe high frequency longitudinal phonon mode previously predicted by the molecular dynamics simulations and for the first time, we reveal low frequency weakly dispersive transverse acoustic mode which softens and exhibits a low-frequency phonon gap when the DPPC lipid transitions into the L α fluid phase. The phonon softening of the high frequency longitudinal excitations and the transformation of the transverse excitations upon the phase transition from the L β'more » to L α phase is explained within the framework of the phonon theory of liquids. These findings illustrate the importance of the collective dynamics of biomembranes and reveal that hydrocarbon tails can act as an efficient mediator in controlling the passive transport across the bilayer plane.« less

Slip-stacking Dynamics for High-Power Proton Beams at Fermilab

DOE Office of Scientific and Technical Information (OSTI.GOV)

Eldred, Jeffrey Scott

Slip-stacking is a particle accelerator configuration used to store two particle beams with different momenta in the same ring. The two beams are longitudinally focused by two radiofrequency (RF) cavities with a small frequency difference between them. Each beam is synchronized to one RF cavity and perturbed by the other RF cavity. Fermilab uses slip-stacking in the Recycler so as to double the power of the 120 GeV proton beam in the Main Injector. This dissertation investigates the dynamics of slip-stacking beams analytically, numerically and experimentally. In the analytic analysis, I find the general trajectory of stable slip-stacking particles andmore » identify the slip-stacking parametric resonances. In the numerical analysis, I characterize the stable phase-space area and model the particle losses. In particular, I evaluate the impact of upgrading the Fermilab Booster cycle-rate from 15 Hz to 20 Hz as part of the Proton Improvement Plan II (PIP-II). The experimental analysis is used to verify my approach to simulating slip-stacking loss. I design a study for measuring losses from the longitudinal single-particle dynamics of slip-stacking as a function of RF cavity voltage and RF frequency separation. I further propose the installation of a harmonic RF cavity and study the dynamics of this novel slip-stacking configuration. I show the harmonic RF cavity cancels out parametric resonances in slip-stacking, reduces emittance growth during slip-stacking, and dramatically enhances the stable phase-space area. The harmonic cavity is expected to reduce slip-stacking losses to far exceed PIP-II requirements. These results raise the possibility of extending slip-stacking beyond the PIP-II era.« less

Advancing Blade Concept (ABC) Technology Demonstrator

DTIC Science & Technology

1981-04-01

simulated 40-knot full-scale speed were conducted in Phase 0 on the Princeton dynamic model tract (Reference 7). Forward flight tests to a...laterally and longitudinally but also to control the thrust sharing between the rotors are presented in Figure 28. Phase II Tests : This model test phase...were rigged to the required values. Control system linearity and hysteresis tests were conducted to determine

Undergraduate medical education programme renewal: a longitudinal context, input, process and product evaluation study.

PubMed

Mirzazadeh, Azim; Gandomkar, Roghayeh; Hejri, Sara Mortaz; Hassanzadeh, Gholamreza; Koochak, Hamid Emadi; Golestani, Abolfazl; Jafarian, Ali; Jalili, Mohammad; Nayeri, Fatemeh; Saleh, Narges; Shahi, Farhad; Razavi, Seyed Hasan Emami

2016-02-01

The purpose of this study was to utilize the Context, Input, Process and Product (CIPP) evaluation model as a comprehensive framework to guide initiating, planning, implementing and evaluating a revised undergraduate medical education programme. The eight-year longitudinal evaluation study consisted of four phases compatible with the four components of the CIPP model. In the first phase, we explored the strengths and weaknesses of the traditional programme as well as contextual needs, assets, and resources. For the second phase, we proposed a model for the programme considering contextual features. During the process phase, we provided formative information for revisions and adjustments. Finally, in the fourth phase, we evaluated the outcomes of the new undergraduate medical education programme in the basic sciences phase. Information was collected from different sources such as medical students, faculty members, administrators, and graduates, using various qualitative and quantitative methods including focus groups, questionnaires, and performance measures. The CIPP model has the potential to guide policy makers to systematically collect evaluation data and to manage stakeholders' reactions at each stage of the reform in order to make informed decisions. However, the model may result in evaluation burden and fail to address some unplanned evaluation questions.

High-affinity 3H-substance P binding to longitudinal muscle membranes of the guinea pig small intestine.

PubMed

Buck, S H; Maurin, Y; Burks, T F; Yamamura, H I

1984-01-30

The binding of 3H-substance P (3H-SP) to longitudinal muscle membranes of the guinea pig small intestine has been characterized. The binding of 3H-SP exhibited a high affinity (Kd = 0.5nM). It was saturable (Bmax = 2 fmoles/mg tissue), reversible, and temperature-dependent. Kinetic studies and competition of 3H-SP binding by unlabeled SP yielded Kd and Ki values, respectively, which were in good agreement with the Kd calculated from saturation studies. The binding of 3H-SP appeared to be dependent on the presence of divalent cations in the incubation buffer. It was displaced by SP and various analogs and fragments in the rank order of SP greater than SP-(2-11) = SP-(3-11) greater than Nle11- SP = physalaemin greater than SP-(4-11) greater than SP-(5-11) greater than eledoisin much greater than SP-(7-11). Our results indicate that 3H-SP binds in longitudinal muscle of the guinea pig small intestine to a biologically relevant receptor which in many respects resembles the SP receptor characterized in the brain and the salivary gland of the rat.

Which emotional regulatory strategy makes Chinese adolescents happier? A longitudinal study.

PubMed

Sang, Biao; Deng, Xinmei; Luan, Ziyan

2014-12-01

Growing interest in emotion regulation is reflected in the studies of cognitive and social development. However, the extant studies mainly highlight how emotion regulation develops based on a western value system. This study utilised a longitudinal design to examine the development of emotion regulation and explored the contributions of different regulatory strategies to emotion experience regarding the early adolescent development period in a Chinese population. A total of 303 Chinese adolescents (age range = 10-14 years) were followed up in a three-phase longitudinal study for 3 years. In each phase of the study, participants completed Adolescents Emotion Regulation Questionnaire and Daily Emotion Scale. Results of hierarchical linear regressions revealed that Chinese adolescents reported more down-regulation. Down-regulation is more effective than up-regulation in enhancing desirable emotion experience and reducing undesirable emotion experience during adolescents' development. Also, the adaptive functions of emotional regulatory strategies in Chinese background were discussed. © 2014 International Union of Psychological Science.

A Longitudinal Study of Families Formed through Reproductive Donation: Parent-Adolescent Relationships and Adolescent Adjustment at Age 14

ERIC Educational Resources Information Center

Golombok, Susan; Ilioi, Elena; Blake, Lucy; Roman, Gabriela; Jadva, Vasanti

2017-01-01

The aim of the 6th phase of this longitudinal study was to establish whether children born through assisted reproduction involving reproductive donation were at risk for psychological problems following the transition to adolescence at age 14 and, if so, to examine the nature of these problems and the mechanisms involved. Eighty-seven families…

INTERNATIONAL CONFERENCE ON SEMICONDUCTOR INJECTION LASERS SELCO-87: Line width of a single longitudinal mode emitted by an AlGaAs heterojunction laser

NASA Astrophysics Data System (ADS)

Bogatov, Alexandr P.; Eliseev, P. G.; Luk'yanov, S. A.; Pak, G. T.; Petrakova, T. V.

1988-11-01

A nonmonotonic dependence of the emission line width on the power was observed for a single longitudinal mode of an AlGaAs heterojunction laser. This behavior could be due to the dependence of the waveguide coefficient of the amplitude-phase coupling on the nature of operation of the laser.

Quantitative Ray Methods for Scattering of Sound by Spherical Shells

DTIC Science & Technology

1991-08-01

certain anonialxis are discussed . A ray synthesis offsp demonstrates a significant longitudinal resonance effect when kLh = nit, n = 1, 2...computations and experiments with tone burst, certain anomalies are discussed . A ray synthesis offsp 4emorstrates a significant longitudinal resonance effect ...Appendices to Chapter 2 A ) Lemb wave damping parameters, phase velocities, and the effect of the breathing mode ................. 47 Rteferences to

Predictors of Disordered Eating in Adolescence and Young Adulthood: A Population-Based, Longitudinal Study of Females and Males in Norway

ERIC Educational Resources Information Center

Abebe, Dawit Shawel; Torgersen, Leila; Lien, Lars; Hafstad, Gertrud S.; von Soest, Tilmann

2014-01-01

We investigated longitudinal predictors for disordered eating from early adolescence to young adulthood (12-34 years) across gender and different developmental phases among Norwegian young people. Survey data from a population-based sample were collected at four time points (T) over a 13-year time span. A population-based sample of 5,679 females…

Ultrasonic wave velocity measurement in small polymeric and cortical bone specimens

NASA Technical Reports Server (NTRS)

Kohles, S. S.; Bowers, J. R.; Vailas, A. C.; Vanderby, R. Jr

1997-01-01

A system was refined for the determination of the bulk ultrasonic wave propagation velocity in small cortical bone specimens. Longitudinal and shear wave propagations were measured using ceramic, piezoelectric 20 and 5 MHz transducers, respectively. Results of the pulse transmission technique were refined via the measurement of the system delay time. The precision and accuracy of the system were quantified using small specimens of polyoxymethylene, polystyrene-butadiene, and high-density polyethylene. These polymeric materials had known acoustic properties, similarity of propagation velocities to cortical bone, and minimal sample inhomogeneity. Dependence of longitudinal and transverse specimen dimensions upon propagation times was quantified. To confirm the consistency of longitudinal wave propagation in small cortical bone specimens (< 1.0 mm), cut-down specimens were prepared from a normal rat femur. Finally, cortical samples were prepared from each of ten normal rat femora, and Young's moduli (Eii), shear moduli (Gij), and Poisson ratios (Vij) were measured. For all specimens (bone, polyoxymethylene, polystyrene-butadiene, and high-density polyethylene), strong linear correlations (R2 > 0.997) were maintained between propagation time and distance throughout the size ranges down to less than 0.4 mm. Results for polyoxymethylene, polystyrene-butadiene, and high-density polyethylene were accurate to within 5 percent of reported literature values. Measurement repeatability (precision) improved with an increase in the wave transmission distance (propagating dimension). No statistically significant effect due to the transverse dimension was detected.

Excitable dynamics in high-Lewis number premixed gas combustion at normal and microgravity

NASA Technical Reports Server (NTRS)

Pearlman, Howard

1995-01-01

Freely-propagating, premixed gas flames in high-Lewis (Le) number, quiescent mixtures are studied experimentally in tubes of various diameter at normal (lg) and microgravity (mu g). A premixture of lean butane and oxygen diluted with helium, argon, neon, nitrogen or a mixture of multiple diluents is examined such that the thermal diffusivity of the mixture (and to a lesser extent, the mass diffusivity of the rate-limiting component) is systematically varied. In effect, different diluents allow variation of the Le without changing the chemistry. The flames are recorded with high speed cinematography and their stability is visually assessed. Different modes of propagation were observed depending on the diameter of the tubes (different conductive heat loss), the composition of the mixture and the g-level. At 1g, four modes of propagation were observed in small and intermediate diameter tubes (large conductive heat loss): (1) steadily propagating flames, (2) radial and longitudinal pulsating flames, (3) 'wavering' flames, and (4) rotating spiral flames. As the diameter of the tube increases, the radial modes become more pronounced while the longitudinal modes systematically disappear. Also, multiple, simultaneous, spatially-separated 'pacemaker' sites are observed in intermediate and large diameter tubes. Each site starts as a small region of high luminosity and develops into a flamelet which assumes the form of one of the fore mentioned modes. These flamelets eventually interact, annihilate each other in their regions of intersection and merge at their newly created free-ends. For very large tubes, radially-propagating wave-trains (believed to be 'trigger waves') are observed. These are analogous to the radial pulsations observed in the smaller diameter tubes. At mu g, three modes of propagation have been observed: (1) steadily propagating flames, (2) radial and longitudinal pulsating flames, and (3) multi-armed, rotating flames. Since the pulsating mode exists at mu g and 1g, buoyant flicker is not the mechanism which drives the pulsations. Moreover, all of the instabilities at 1g and mu g have characteristic frequencies on the O(100Hz). This value is lower than the fundamental, longitudinal acoustic frequencies of the tubes which suggests that the instabilities are not acoustically driven. The patterns formed by this reaction bear remarkable similarities with the patterns formed in most excitable media when the behavior of the system is driven by couplings between chemical reaction and diffusion (e.g., Belousov-Zhabotinsky reaction, Patterns in slime molds, spiral waves in the retina of a bird's eye). While it is recognized that the chemical mechanism associated with this premixed gas reaction is exponentially sensitive to temperature and undoubtedly different from those which govern previously observed excitable media (most are isothermal, or weakly exothermic, liquid phase reactions), similar spatial and temporal patterns should not come as a complete surprise considering heat and mass diffusion are self similar. It is concluded that this premixed gas system is a definitive example of a diffusive-thermal, gas-phase oscillator based on these experimental results and their favorable comparison with theory.

Diurnal stratospheric tide in meridional wind, 30 to 60 KM, by season and monthly mean temperatures, 20 to 60 KM, at 80 deg N and to 0 deg N

NASA Technical Reports Server (NTRS)

Nastrom, G. D.; Belmont, A. D.

1975-01-01

The diurnal component in meridional wind was observed for each season at twelve rocket stations. Amplitudes and phases are presented as a function of height-latitude or as vertical profiles. Many of the gross features of the tide persist throughout the year, but as they migrate in height and latitude the amplitude or phase at a given location may undergo large changes with season. Longitudinal variations in the diurnal tide are found in the mid-stratosphere, and it is suggested they are coupled with longitudinal variations in the tropospheric temperature structure.

Effects of laser source parameters on the generation of narrow band and directed laser ultrasound

NASA Technical Reports Server (NTRS)

Spicer, James B.; Deaton, John B., Jr.; Wagner, James W.

1992-01-01

Predictive and prescriptive modeling of laser arrays is performed to demonstrate the effects of the extension of array elements on laser array performance. For a repetitively pulsed laser source (the temporal laser array), efficient frequency compression is best achieved by detecting longitudinal waves off-epicenter in plates where the source size and shape directly influence the longitudinal wave shape and duration; the longitudinal array may be tailored for a given repetition frequency to yield efficient overtone energy compression into the fundamental frequency band. For phased arrays, apparent array directivity is heavily influenced by array element size.

A Simple, Inexpensive Model to Demonstrate How Contraction of GI Longitudinal Smooth Muscle Promotes Propulsion

ERIC Educational Resources Information Center

Lujan, Heidi L.; DiCarlo, Stephen E.

2015-01-01

Peristalis is a propulsive activity that involves both circular and longitudinal muscle layers of the esophagus, distal stomach, and small and large intestines. During peristalsis, the circular smooth muscle contracts behind (on the orad side) the bolus and relaxes in front (on the aborad side) of the bolus. At the same time, the longitudinal…

Turbulent flow separation control through passive techniques

NASA Technical Reports Server (NTRS)

Lin, J. C.; Howard, F. G.; Selby, G. V.

1989-01-01

Several passive separation control techniques for controlling moderate two-dimensional turbulent flow separation over a backward-facing ramp are studied. Small transverse and swept grooves, passive porous surfaces, large longitudinal grooves, and vortex generators were among the techniques used. It was found that, unlike the transverse and longitudinal grooves of an equivalent size, the 45-deg swept-groove configurations tested tended to enhance separation.

Second- to third-trimester longitudinal growth assessment for prediction of small-for-gestational age and late fetal growth restriction.

PubMed

Caradeux, J; Eixarch, E; Mazarico, E; Basuki, T R; Gratacós, E; Figueras, F

2018-02-01

Detection of fetal growth restriction (FGR) remains poor and most screening strategies rely on cross-sectional evaluation of fetal size during the third trimester. A longitudinal and individualized approach has been proposed as an alternative method of evaluation. The aim of this study was to compare second- to third-trimester longitudinal growth assessment to cross-sectional evaluation in the third trimester for the prediction of small-for-gestational age (SGA) and late FGR in low-risk singleton pregnancy. This was a prospective cohort study of 2696 unselected consecutive low-risk singleton pregnancies scanned at 21 ± 2 and 32 ± 2 weeks. For cross-sectional growth assessment, abdominal circumference (AC) measurements were transformed to z-values according the 21st-INTERGROWTH standards. Longitudinal growth assessment was performed by calculating the AC z-velocity and the second- to third-trimester AC conditional growth centile. Longitudinal assessment was compared with cross-sectional assessment at 32 weeks. Association of cross-sectional and longitudinal evaluations with SGA and late FGR was assessed by logistic regression analysis. Predictive performance was determined by receiver-operating characteristics curve analysis. In total, 210 (7.8%) newborns were classified as SGA and 103 (3.8%) as late FGR. Neither longitudinal measurement improved the association with SGA or late FGR provided by cross-sectional evaluation of AC z-score at 32 weeks. Areas under the curves of AC z-velocity and conditional AC growth were significantly smaller than those of cross-sectional AC z-scores (P < 0.001), although AC z-velocity performed significantly better than did conditional AC growth (P < 0.001). Longitudinal assessment of fetal growth from the second to third trimester has a low predictive capacity for SGA and late FGR in low-risk singleton pregnancy compared with cross-sectional growth evaluation. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.

PHYSICAL PROPERTIES OF LARGE AND SMALL GRANULES IN SOLAR QUIET REGIONS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yu Daren; Xie Zongxia; Hu Qinghua

The normal mode observations of seven quiet regions obtained by the Hinode spacecraft are analyzed to study the physical properties of granules. An artificial intelligence technique is introduced to automatically find the spatial distribution of granules in feature spaces. In this work, we investigate the dependence of granular continuum intensity, mean Doppler velocity, and magnetic fields on granular diameter. We recognized 71,538 granules by an automatic segmentation technique and then extracted five properties: diameter, continuum intensity, Doppler velocity, and longitudinal and transverse magnetic flux density to describe the granules. To automatically explore the intrinsic structures of the granules in themore » five-dimensional parameter space, the X-means clustering algorithm and one-rule classifier are introduced to define the rules for classifying the granules. It is found that diameter is a dominating parameter in classifying the granules and two families of granules are derived: small granules with diameters smaller than 1.''44, and large granules with diameters larger than 1.''44. Based on statistical analysis of the detected granules, the following results are derived: (1) the averages of diameter, continuum intensity, and Doppler velocity in the upward direction of large granules are larger than those of small granules; (2) the averages of absolute longitudinal, transverse, and unsigned flux density of large granules are smaller than those of small granules; (3) for small granules, the average of continuum intensity increases with their diameters, while the averages of Doppler velocity, transverse, absolute longitudinal, and unsigned magnetic flux density decrease with their diameters. However, the mean properties of large granules are stable; (4) the intensity distributions of all granules and small granules do not satisfy Gaussian distribution, while that of large granules almost agrees with normal distribution with a peak at 1.04 I{sub 0}.« less

Imaging of cardiac perfusion of free-breathing small animals using dynamic phase-correlated micro-CT

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sawall, Stefan; Kuntz, Jan; Socher, Michaela

Purpose:Mouse models of cardiac diseases have proven to be a valuable tool in preclinical research. The high cardiac and respiratory rates of free breathing mice prohibit conventional in vivo cardiac perfusion studies using computed tomography even if gating methods are applied. This makes a sacrification of the animals unavoidable and only allows for the application of ex vivo methods. Methods: To overcome this issue the authors propose a low dose scan protocol and an associated reconstruction algorithm that allows for in vivo imaging of cardiac perfusion and associated processes that are retrospectively synchronized to the respiratory and cardiac motion ofmore » the animal. The scan protocol consists of repetitive injections of contrast media within several consecutive scans while the ECG, respiratory motion, and timestamp of contrast injection are recorded and synchronized to the acquired projections. The iterative reconstruction algorithm employs a six-dimensional edge-preserving filter to provide low-noise, motion artifact-free images of the animal examined using the authors' low dose scan protocol. Results: The reconstructions obtained show that the complete temporal bolus evolution can be visualized and quantified in any desired combination of cardiac and respiratory phase including reperfusion phases. The proposed reconstruction method thereby keeps the administered radiation dose at a minimum and thus reduces metabolic inference to the animal allowing for longitudinal studies. Conclusions: The authors' low dose scan protocol and phase-correlated dynamic reconstruction algorithm allow for an easy and effective way to visualize phase-correlated perfusion processes in routine laboratory studies using free-breathing mice.« less

Optimal Number and Allocation of Data Collection Points for Linear Spline Growth Curve Modeling: A Search for Efficient Designs

ERIC Educational Resources Information Center

Wu, Wei; Jia, Fan; Kinai, Richard; Little, Todd D.

2017-01-01

Spline growth modelling is a popular tool to model change processes with distinct phases and change points in longitudinal studies. Focusing on linear spline growth models with two phases and a fixed change point (the transition point from one phase to the other), we detail how to find optimal data collection designs that maximize the efficiency…

Longitudinal spatial coherence gated high-resolution tomography and quantitative phase microscopy of biological cells and tissues with uniform illumination

NASA Astrophysics Data System (ADS)

Mehta, Dalip Singh; Ahmad, Azeem; Dubey, Vishesh; Singh, Veena; Butola, Ankit; Mohanty, Tonmoy; Nandi, Sreyankar

2018-02-01

We report longitudinal spatial coherence (LSC) gated high-resolution tomography and quantitative phase microscopy of biological cells and tissues with uniform illumination using laser as a light source. To accomplish this a pseudo thermal light source was synthesized by passing laser beams through an optical system, which is basically a speckle reduction system with combined effect of spatial, temporal, angular and polarisation diversity. The longitudinal spatial coherence length of such light was significantly reduced by synthesizing a pseudo thermal source with the combined effect of spatial, angular and temporal diversity. This results in a low spatially coherent (i.e., broad angular frequency spectrum) light source with narrow temporal frequency spectrum. Light from such a pseudo thermal light source was passed through an interference microscope with varying magnification, such as, 10X and 50X. The interference microscope was used for full-field OCT imaging of multilayer objects and topography of industrial objects. Experimental results of optical sectioning of multilayer biological objects with high axial-resolution less than 10μm was achieved which is comparable to broadband white light source. The synthesized light source with reduced speckles having uniform illumination on the sample, which can be very useful for fluorescence microscopy as well as quantitative phase microscopy with less phase noise. The present system does not require any dispersion compensation optical system for biological samples as a highly monochromatic light source is used.

Microstructural stability of fine-grained fully lamellar XD TiAl alloys by step aging

NASA Astrophysics Data System (ADS)

Zhu, Hanliang; Maruyama, K.; Seo, D. Y.; Au, P.

2005-05-01

XD TiAl alloys (Ti-45 and 47Al-2Nb-2Mn+0.8 vol pct TiB2) (at. pct) were oil quenched to produce fine-grained fully lamellar (FGFL) structures, and aging treatments at different temperatures for different durations were carried out to stabilize the FGFL structures. Microstructural examinations show that the aging treatments cause phase transformation of α 2 to γ, resulting in stabilization of the lamellar structure, as indicated by a significant decrease in α 2 volume fraction. However, several degradation processes are also introduced. After aging, within lamellar colonies, the α 2 lamellae become finer due to dissolution, whereas most of the γ lamellae coarsen. The dissolution of α 2 involves longitudinal dissolution and lateral dissolution. In addition, at lamellar colony boundaries, lamellar termination migration, nucleation and growth of γ grains, and discontinuous coarsening occur. With the exception of longitudinal dissolution, all the other transformation modes are considered as degradation processes as they result in a reduction in α 2/ γ interfaces. Different phase transformation modes are present to varying degrees in the aged FGFL structures, depending on aging conditions and Al content. A multiple step aging reduces the drive force for phase transformation at high temperature by promoting phase transformation via longitudinal dissolution at low temperatures. As a result, this aging procedure effectively stabilizes the lamellar structure and suppresses other degradation processes. Therefore, the multiple step aging is suggested to be an optimal aging condition for stabilizing FGFL XD TiAl alloys.

A New Method to Directly Measure the Jeans Scale of the Intergalactic Medium Using Close Quasar Pairs

NASA Astrophysics Data System (ADS)

Rorai, Alberto; Hennawi, Joseph F.; White, Martin

2013-10-01

Although the baryons in the intergalactic medium (IGM) trace dark matter fluctuations on megaparsec scales, on smaller scales ~100 kpc, fluctuations are suppressed because the finite temperature gas is pressure supported against gravity, analogous to the classical Jeans argument. This Jeans filtering scale, which quantifies the small-scale structure of the IGM, has fundamental cosmological implications. First, it provides a thermal record of heat injected by ultraviolet photons during cosmic reionization events, and thus constrains the thermal and reionization history of the universe. Second, the Jeans scale determines the clumpiness of the IGM, a critical ingredient in models of cosmic reionization. Third, it sets the minimum mass scale for gravitational collapse from the IGM, and hence plays a pivotal role in galaxy formation. Unfortunately, it is extremely challenging to measure the Jeans scale via the standard technique of analyzing purely longitudinal Lyα forest spectra, because the thermal Doppler broadening of absorption lines along the line-of-sight, is highly degenerate with Jeans smoothing. In this work, we show that the Jeans filtering scale can be directly measured by characterizing the coherence of correlated Lyα forest absorption in close quasar pairs, with separations small enough ~100 kpc to resolve it. We present a novel technique for this purpose, based on the probability density function (PDF) of phase angle differences of homologous longitudinal Fourier modes in close quasar pair spectra. A Bayesian formalism is introduced based on the phase angle PDF, and Markov Chain Monte Carlo techniques are used to characterize the precision of a hypothetical Jeans scale measurement, and explore degeneracies with other thermal parameters governing the IGM. A semi-analytical model of the Lyα forest is used to generate a large grid (500) of thermal models from a dark matter only simulation. Our full parameter study indicates that a realistic sample of only 20 close quasar pair spectra can pinpoint the Jeans scale to ~= 5% precision, independent of the amplitude T 0 and slope γ of the temperature-density relation of the IGM T=T_0(\\rho / {\\bar{\\rho }})^{\\gamma -1}. This exquisite sensitivity arises because even long-wavelength one-dimensional Fourier modes ~10 Mpc, i.e., two orders of magnitude larger than the Jeans scale, are nevertheless dominated by projected small-scale three-dimensional (3D) power. Hence phase angle differences between all modes of quasar pair spectra actually probe the shape of the 3D power spectrum on scales comparable to the pair separation. We show that this new method for measuring the Jeans scale is unbiased and is insensitive to a battery of systematics that typically plague Lyα forest measurements, such as continuum fitting errors, imprecise knowledge of the noise level and/or spectral resolution, and metal-line absorption.

A NEW METHOD TO DIRECTLY MEASURE THE JEANS SCALE OF THE INTERGALACTIC MEDIUM USING CLOSE QUASAR PAIRS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rorai, Alberto; Hennawi, Joseph F.; White, Martin

2013-10-01

Although the baryons in the intergalactic medium (IGM) trace dark matter fluctuations on megaparsec scales, on smaller scales ∼100 kpc, fluctuations are suppressed because the finite temperature gas is pressure supported against gravity, analogous to the classical Jeans argument. This Jeans filtering scale, which quantifies the small-scale structure of the IGM, has fundamental cosmological implications. First, it provides a thermal record of heat injected by ultraviolet photons during cosmic reionization events, and thus constrains the thermal and reionization history of the universe. Second, the Jeans scale determines the clumpiness of the IGM, a critical ingredient in models of cosmic reionization.more » Third, it sets the minimum mass scale for gravitational collapse from the IGM, and hence plays a pivotal role in galaxy formation. Unfortunately, it is extremely challenging to measure the Jeans scale via the standard technique of analyzing purely longitudinal Lyα forest spectra, because the thermal Doppler broadening of absorption lines along the line-of-sight, is highly degenerate with Jeans smoothing. In this work, we show that the Jeans filtering scale can be directly measured by characterizing the coherence of correlated Lyα forest absorption in close quasar pairs, with separations small enough ∼100 kpc to resolve it. We present a novel technique for this purpose, based on the probability density function (PDF) of phase angle differences of homologous longitudinal Fourier modes in close quasar pair spectra. A Bayesian formalism is introduced based on the phase angle PDF, and Markov Chain Monte Carlo techniques are used to characterize the precision of a hypothetical Jeans scale measurement, and explore degeneracies with other thermal parameters governing the IGM. A semi-analytical model of the Lyα forest is used to generate a large grid (500) of thermal models from a dark matter only simulation. Our full parameter study indicates that a realistic sample of only 20 close quasar pair spectra can pinpoint the Jeans scale to ≅ 5% precision, independent of the amplitude T{sub 0} and slope γ of the temperature-density relation of the IGM T=T{sub 0}(ρ/ ρ-bar ){sup γ-1}. This exquisite sensitivity arises because even long-wavelength one-dimensional Fourier modes ∼10 Mpc, i.e., two orders of magnitude larger than the Jeans scale, are nevertheless dominated by projected small-scale three-dimensional (3D) power. Hence phase angle differences between all modes of quasar pair spectra actually probe the shape of the 3D power spectrum on scales comparable to the pair separation. We show that this new method for measuring the Jeans scale is unbiased and is insensitive to a battery of systematics that typically plague Lyα forest measurements, such as continuum fitting errors, imprecise knowledge of the noise level and/or spectral resolution, and metal-line absorption.« less

Amorphous SiC/c-ZnO-Based Quasi-Lamb Mode Sensor for Liquid Environments.

PubMed

Caliendo, Cinzia; Hamidullah, Muhammad; Laidoudi, Farouk

2017-05-25

The propagation of the quasi-Lamb modes along a-SiC/ZnO thin composite plates was modeled and analysed with the aim to design a sensor able to detect the changes in parameters of a liquid environment, such as added mass and viscosity changes. The modes propagation was modeled by numerically solving the system of coupled electro-mechanical field equations in three media. The mode shape, the power flow, the phase velocity, and the electroacoustic coupling efficiency (K²) of the modes were calculated, specifically addressing the design of enhanced-coupling, microwave frequency sensors for applications in probing the solid/liquid interface. Three modes were identified that have predominant longitudinal polarization, high phase velocity, and quite good K²: the fundamental quasi symmetric mode (qS₀) and two higher order quasi-longitudinal modes (qL₁ and qL₂) with a dominantly longitudinal displacement component in one plate side. The velocity and attenuation of these modes were calculated for different liquid viscosities and added mass, and the gravimetric and viscosity sensitivities of both the phase velocity and attenuation were theoretically calculated. The present study highlights the feasibility of the a-SiC/ZnO acoustic waveguides for the development of high-frequency, integrated-circuit compatible electroacoustic devices suitable for working in a liquid environment.

Anterior longitudinal ligament injuries in whiplash may lead to cervical instability.

PubMed

Stemper, Brian D; Yoganandan, Narayan; Pintar, Frank A; Rao, Raj D

2006-07-01

Although whiplash injuries account for a significant annual cost to society, the exact mechanism of injury and affected tissues remain unknown. Previous investigations documented injuries to the cervical anterior longitudinal ligament in whiplash. The present investigation implemented a comprehensively validated computational model to quantify level-dependent distraction magnitudes of this structure in whiplash. Maximum ligament distractions approached failure levels, particularly in middle to lower cervical levels, and occurred during the initial phase of head-neck kinematics. In particular, the C5-C6 anterior longitudinal ligament sustained distraction magnitudes as high as 2.6mm during the retraction phase, corresponding to 56% of distraction necessary to result in ligament failure. Present results demonstrated that anterior structures in the lower cervical spine may be susceptible to injury through excess distraction during the retraction phase of whiplash, which likely occurs prior to head restraint contact. Susceptibility of these structures is likely due to non-physiologic loading placed on the cervical spinal column as the head translates posteriorly relative to the thorax. Injury to anterior spinal structures can result in clinical indications including cervical instability in extension, axial rotation, and lateral bending modes. Mitigation of whiplash injury may be achieved by minimizing head retraction during initial stages of whiplash.

Enhanced understanding of the relationship between erection and satisfaction in ED treatment: application of a longitudinal mediation model.

PubMed

Bushmakin, A G; Cappelleri, J C; Symonds, T; Stecher, V J

2014-01-01

To apportion the direct effect and the indirect effect (through erections) that sildenafil (vs placebo) has on individual satisfaction and couple satisfaction over time, longitudinal mediation modeling was applied to outcomes on the Sexual Experience Questionnaire. The model included data from weeks 4 and 10 (double-blind phase) and week 16 (open-label phase) of a controlled study. Data from 167 patients with erectile dysfunction (ED) were available for analysis. Estimation of statistical significance was based on bootstrap simulations, which allowed inferences at and between time points. Percentages (and corresponding 95% confidence intervals) for direct and indirect effects of treatment were calculated using the model. For the individual satisfaction and couple satisfaction domains, direct treatment effects were negligible (not statistically significant) whereas indirect treatment effects via the erection domain represented >90% of the treatment effects (statistically significant). Week 4 vs week 10 percentages of direct and indirect effects were not statistically different, indicating that the mediation effects are longitudinally invariant. As there was no placebo arm in the open-label phase, mediation effects at week 16 were not estimable. In conclusion, erection has a crucial role as a mediator in restoring individual satisfaction and couple satisfaction in men with ED treated with sildenafil.

Simultaneous Transverse and Longitudinal Oscillations in a Quiescent Prominence Triggered by a Coronal Jet

NASA Astrophysics Data System (ADS)

Zhang, Q. M.; Li, D.; Ning, Z. J.

2017-12-01

In this paper, we report our multiwavelength observations of the simultaneous transverse and longitudinal oscillations in a quiescent prominence. The prominence was observed by the Global Oscillation Network Group and by the Atmospheric Imaging Assembly on board the Solar Dynamics Observatory on 2015 June 29. A GOES C2.4 flare took place in NOAA active region 12373, which was associated with a pair of short ribbons and a remote ribbon. During the impulsive phase of the flare, a coronal jet spurted out of the primary flare site and propagated in the northwest direction at an apparent speed of ∼224 km s‑1. Part of the jet stopped near the remote ribbon. The remaining part continued moving forward before stopping to the east of the prominence. Once the jet encountered the prominence, it pushed the prominence to oscillate periodically. The transverse oscillation of the eastern part (EP) of prominence can be divided into two phases. In phase I, the initial amplitude, velocity, period, and damping timescale are ∼4.5 Mm, ∼20 km s‑1, ∼25 minutes, and ∼7.5 hr, respectively. The oscillation lasted for two cycles. In phase II, the initial amplitude increases to ∼11.3 Mm, while the initial velocity halves to ∼10 km s‑1. The period increases by a factor of ∼3.5. With a damping timescale of ∼4.4 hr, the oscillation lasted for about three cycles. The western part of prominence also experienced transverse oscillation. The initial amplitude is only ∼2 Mm and the velocity is less than 10 km s‑1. The period (∼27 minutes) is slightly longer than that of the EP in phase I. The oscillation lasted for about four cycles with the shortest damping timescale (∼1.7 hr). To the east of prominence, a handful of horizontal threads experienced longitudinal oscillation. The initial amplitude, velocity, period, and damping timescale are ∼52 Mm, ∼50 km s‑1, ∼99 minutes, and 2.5 hr, respectively. To our knowledge, this is the first report of simultaneous transverse and longitudinal prominence oscillations triggered by a coronal jet.

RF Curves for Extraction from the Accumulator

DOE Office of Scientific and Technical Information (OSTI.GOV)

McGinnis, Dav; /Fermilab

2002-03-10

Since the start of Run IIa, the RF curves for the extraction process from the Accumulator have been based on an algorithm described in Pbar Note 636. There are a number of problems with this procedure that result in a dilution of the longitudinal phase space of the extracted beam. The procedure consists of a number of steps in which the frequency curve during each process is a linear time ramp. For a constant bend field, the synchronous phase angle is given as: {Lambda} = sin({phi}{sub s}) = -h/{eta} (1/f{sub rf}){sup 2}df{sub rf}/dt/qV/pc where h is the harmonic number ofmore » the RF. Equation (1) shows that if the frequency curve consists of a number of linear time ramps with different slopes, there will be discontinuities in the synchronous phase. These discontinuities in the synchronous phase will lead to dipole oscillations of the beam in the RF bucket. The discontinuities observed for the present RF curves are about 10 degrees. In the procedure outlined in Pbar Note 636, the RF bucket is formed on the high energy edge of the rectangular momentum distribution. As the RF bucket is pulled away from the core, it is also programmed to increase in area. If the distribution is not perfectly rectangular, or if the bucket is not formed at the edge of the distribution, the growing bucket will gather up more particles at the edges of the bucket resulting in a substantial increase of longitudinal emittance. Finally, it is fairly difficult to prepare a rectangular momentum distribution and keep it rectangular for extended periods of time. Once the rectangular distribution is prepared, the core momentum cooling must be turned off. If there is a delay in the extraction process, the sharp edges of the rectangular distribution will soon diffuse. With the momentum cooling disabled, the longitudinal emittance of the core will grow resulting in larger longitudinal emittances for the extracted beam.« less

Subjective Well-Being: The Constructionist Point of View. A Longitudinal Study to Verify the Predictive Power of Top-Down Effects and Bottom-Up Processes

ERIC Educational Resources Information Center

Leonardi, Fabio; Spazzafumo, Liana; Marcellini, Fiorella

2005-01-01

Based on the constructionist point of view applied to Subjective Well-Being (SWB), five hypotheses were advanced about the predictive power of the top-down effects and bottom-up processes over a five years period. The sample consisted of 297 respondents, which represent the Italian sample of a European longitudinal survey; the first phase was…

Ultrasound shear wave imaging

NASA Astrophysics Data System (ADS)

Ye, Shigong; Wu, Junru

2000-05-01

Shear wave propagation properties including phase velocity and attenuation coefficient are indispensable information in materials characterization and nondestructive evaluation. A computer controlled scanning shear-wave ultrasonic imaging system has been developed. It consists of a pair of focusing broadband pvdf transducers of central frequency of 50 MHz immersed in distilled water. Shear waves in a solid specimen are generated by mode-conversion. When ultrasonic waves generated by one of the pvdf transducers impinge upon a solid specimen from water with angle of incidence of θ that is greater than θcr, the critical angle of the longitudinal wave in the solid, only shear waves can propagate in the solid and longitudinal waves become evanescent waves. The shear waves pass through the specimen and received by the other pvdf transducer. Meanwhile, the specimen was scanned by a stepped motor of a step of 10 μm. The system was used to generated shear waves amplitude and phase velocity images of bone specimen of 1280 μm and they are compared with their longitudinal wave counterparts. The results have shown shear wave images can provide additional shear modulus and shear viscous information that longitudinal waves can't provide. The lateral resolution of 60 μm was achieved using shear wave imaging technique applied in bone sample.

Longitudinal Study Using a Standardized Test Battery as Predictors of Student Outcomes in a Rural County School System.

ERIC Educational Resources Information Center

Twale, Darla J.; Thompson, Mary J.

This longitudinal study focused on predicting student outcomes through multiple test scores and vocational preferences using standardized instruments and self-reports of career plans. A total of 444 students in the class of 1986 were enrolled in either a non-vocational or vocational curriculum at one of 4 high schools in a small, rural,…

Asymptotic sideslip angle and yaw rate decoupling control in four-wheel steering vehicles

NASA Astrophysics Data System (ADS)

Marino, Riccardo; Scalzi, Stefano

2010-09-01

This paper shows that, for a four-wheel steering vehicle, a proportional-integral (PI) active front steering control and a PI active rear steering control from the yaw rate error together with an additive feedforward reference signal for the vehicle sideslip angle can asymptotically decouple the lateral velocity and the yaw rate dynamics; that is the control can set arbitrary steady state values for lateral speed and yaw rate at any longitudinal speed. Moreover, the PI controls can suppress oscillatory behaviours by assigning real stable eigenvalues to a widely used linearised model of the vehicle steering dynamics for any value of longitudinal speed in understeering vehicles. In particular, the four PI control parameters are explicitly expressed in terms of the three real eigenvalues to be assigned. No lateral acceleration and no lateral speed measurements are required. The controlled system maintains the well-known advantages of both front and rear active steering controls: higher controllability, enlarged bandwidth for the yaw rate dynamics, suppressed resonances, new stable cornering manoeuvres and improved manoeuvrability. In particular, zero lateral speed may be asymptotically achieved while controlling the yaw rate: in this case comfort is improved since the phase lag between lateral acceleration and yaw rate is reduced. Also zero yaw rate can be asymptotically achieved: in this case additional stable manoeuvres are obtained in obstacle avoidance. Several simulations, including step references and moose tests, are carried out on a standard small SUV CarSim model to explore the robustness with respect to unmodelled effects such as combined lateral and longitudinal tyre forces, pitch, roll and driver dynamics. The simulations confirm the decoupling between the lateral velocity and the yaw rate and show the advantages obtained by the proposed control: reduced lateral speed or reduced yaw rate, suppressed oscillations and new stable manoeuvres.

In vivo microsampling to capture the elusive exposome

NASA Astrophysics Data System (ADS)

Bessonneau, Vincent; Ings, Jennifer; McMaster, Mark; Smith, Richard; Bragg, Leslie; Servos, Mark; Pawliszyn, Janusz

2017-03-01

Loss and/or degradation of small molecules during sampling, sample transportation and storage can adversely impact biological interpretation of metabolomics data. In this study, we performed in vivo sampling using solid-phase microextraction (SPME) in combination with non-targeted liquid chromatography and high-resolution tandem mass spectrometry (LC-MS/MS) to capture the fish tissue exposome using molecular networking analysis, and the results were contrasted with molecular differences obtained with ex vivo SPME sampling. Based on 494 MS/MS spectra comparisons, we demonstrated that in vivo SPME sampling provided better extraction and stabilization of highly reactive molecules, such as 1-oleoyl-sn-glycero-3-phosphocholine and 1-palmitoleoyl-glycero-3-phosphocholine, from fish tissue samples. This sampling approach, that minimizes sample handling and preparation, offers the opportunity to perform longitudinal monitoring of the exposome in biological systems and improve the reliability of exposure-measurement in exposome-wide association studies.

In vivo microsampling to capture the elusive exposome

PubMed Central

Bessonneau, Vincent; Ings, Jennifer; McMaster, Mark; Smith, Richard; Bragg, Leslie; Servos, Mark; Pawliszyn, Janusz

2017-01-01

Loss and/or degradation of small molecules during sampling, sample transportation and storage can adversely impact biological interpretation of metabolomics data. In this study, we performed in vivo sampling using solid-phase microextraction (SPME) in combination with non-targeted liquid chromatography and high-resolution tandem mass spectrometry (LC-MS/MS) to capture the fish tissue exposome using molecular networking analysis, and the results were contrasted with molecular differences obtained with ex vivo SPME sampling. Based on 494 MS/MS spectra comparisons, we demonstrated that in vivo SPME sampling provided better extraction and stabilization of highly reactive molecules, such as 1-oleoyl-sn-glycero-3-phosphocholine and 1-palmitoleoyl-glycero-3-phosphocholine, from fish tissue samples. This sampling approach, that minimizes sample handling and preparation, offers the opportunity to perform longitudinal monitoring of the exposome in biological systems and improve the reliability of exposure-measurement in exposome-wide association studies. PMID:28266605

Development of CAD prototype system for Crohn's disease

NASA Astrophysics Data System (ADS)

Oda, Masahiro; Kitasaka, Takayuki; Furukawa, Kazuhiro; Watanabe, Osamu; Ando, Takafumi; Goto, Hidemi; Mori, Kensaku

2010-03-01

The purpose of this paper is to present a CAD prototype system for Crohn's disease. Crohn's disease causes inflammation or ulcers of the gastrointestinal tract. The number of patients of Crohn's disease is increasing in Japan. Symptoms of Crohn's disease include intestinal stenosis, longitudinal ulcers, and fistulae. Optical endoscope cannot pass through intestinal stenosis in some cases. We propose a new CAD system using abdominal fecal tagging CT images for efficient diagnosis of Crohn's disease. The system displays virtual unfolded (VU), virtual endoscopic, curved planar reconstruction, multi planar reconstruction, and outside views of both small and large intestines. To generate the VU views, we employ a small and large intestines extraction method followed by a simple electronic cleansing method. The intestine extraction is based on the region growing process, which uses a characteristic that tagged fluid neighbor air in the intestine. The electronic cleansing enables observation of intestinal wall under tagged fluid. We change the height of the VU views according to the perimeter of the intestine. In addition, we developed a method to enhance the longitudinal ulcer on views of the system. We enhance concave parts on the intestinal wall, which are caused by the longitudinal ulcer, based on local intensity structure analysis. We examined the small and the large intestines of eleven CT images by the proposed system. The VU views enabled efficient observation of the intestinal wall. The height change of the VU views helps finding intestinal stenosis on the VU views. The concave region enhancement made longitudinal ulcers clear on the views.

Longitudinal Associations Between Observed and Perceived Neighborhood Food Availability and Body Mass Index in a Multiethnic Urban Sample.

PubMed

Zenk, Shannon N; Mentz, Graciela; Schulz, Amy J; Johnson-Lawrence, Vicki; Gaines, Causandra R

2017-02-01

Blacks, Hispanics, and women of lower socioeconomic status tend to have a higher risk of obesity. Numerous studies over the past decade examined the role of the neighborhood food environment in body weight. However, few were longitudinal. This longitudinal study examined whether multiple measures of neighborhood food availability were associated with body mass index (BMI) in a predominately Black and Hispanic adult sample living in low- to moderate-income urban neighborhoods. This longitudinal study used two waves of data (2002, 2008), including interviewer-measured height and weight, from a community survey of adults ( n = 219). In both 2002 and 2008, multiple measures characterized neighborhood food availability: GIS-derived availability of retail food outlets (large grocery store, small grocery store, convenience store, liquor stores), observed fruit and vegetable availability (count of stores selling 10 or more fresh fruit or vegetable varieties), and perceived fruit and vegetable access. Random intercept models estimated multivariable associations, controlling for individual-level demographics and neighborhood median household income. Small grocery store availability was associated with 1.22-unit increase in BMI ( p = .047), while each unit increase in perceived fruit and vegetable access was associated with a 0.69-unit decrease in BMI ( p = .055). BMI was not associated with large grocery store, convenience store, or liquor store availability, or with observed fruit and vegetable availability. Findings suggest that improving the neighborhood food environment, particularly at small grocery stores, may help urban residents living in low- to moderate-income neighborhoods achieve healthier body weights over time.

Crohn's disease in Japan: diagnostic criteria and epidemiology.

PubMed

Yao, T; Matsui, T; Hiwatashi, N

2000-10-01

New diagnostic criteria for Crohn's disease and a review of Japanese epidemiologic studies are presented. New diagnostic criteria for Crohn's disease were established by the Research Committee of Inflammatory Bowel Disease, set up by the Japanese Ministry of Health and Welfare. For a definite diagnosis one of the following three conditions is required: 1) longitudinal ulcer or luminal deformity induced by longitudinal ulcer or cobblestone pattern, 2) intestinal small aphthous ulcerations arranged in a longitudinal fashion for at least three months plus noncaseating granulomas, and 3) multiple small aphthous ulcerations in both the upper and lower digestive tract not necessarily with longitudinal arrangement, for at least three months, plus noncaseating granulomas. Moreover, ulcerative colitis, ischemic enterocolitis, and acute infectious enterocolitis should be excluded. Data from the Japanese Ministry of Health and Welfare, in addition to data collected from two study groups, these being the two largest studies in Japan, are reviewed with regard to epidemiology. The number of patients with Crohn's disease has increased remarkably. The prevalence and the annual incidence of patients with Crohn's disease in Japan were estimated to be approximately 2.9 and 0.6 per 10(5) population in 1986, respectively, and 13.5 and 1.2 per 10(5) population in 1998. Characteristic features of Crohn's disease in Japan are that the male-female ratio exceeds 2, and that there is no second peak of incidence in the age group of 55 to 65 years. Clinically, Crohn's disease with only multiple small aphthous ulcerations, which is the earliest stage of the disease that is diagnosable, was found in 5 percent of patients.

Predictors of Early versus Later Spelling Development in Danish

ERIC Educational Resources Information Center

Nielsen, Anne-Mette Veber; Juul, Holger

2016-01-01

The present study examined phoneme awareness, phonological short term memory, letter knowledge, rapid automatized naming (RAN), and visual-verbal paired associate learning (PAL) as longitudinal predictors of spelling skills in an early phase (Grade 2) and a later phase (Grade 5) of development in a sample of 140 children learning to spell in the…

Comparison of the ferromagnetic Blume-Emery-Griffiths model and the AF spin-1 longitudinal Ising model at low temperature

NASA Astrophysics Data System (ADS)

Thomaz, M. T.; Corrêa Silva, E. V.

2016-03-01

We derive the exact Helmholtz free energy (HFE) of the standard and staggered one-dimensional Blume-Emery-Griffiths (BEG) model in the presence of an external longitudinal magnetic field. We discuss in detail the thermodynamic behavior of the ferromagnetic version of the model, which exhibits magnetic field-dependent plateaux in the z-component of its magnetization at low temperatures. We also study the behavior of its specific heat and entropy, both per site, at finite temperature. The degeneracy of the ground state, at T=0, along the lines that separate distinct phases in the phase diagram of the ferromagnetic BEG model is calculated, extending the study of the phase diagram of the spin-1 antiferromagnetic (AF) Ising model in S.M. de Souza and M.T. Thomaz, J. Magn. and Magn. Mater. 354 (2014) 205 [5]. We explore the implications of the equality of phase diagrams, at T=0, of the ferromagnetic BEG model with K/|J| = - 2 and of the spin-1 AF Ising model for D/|J| > 1/2.

Effects of magnetic field strength and particle aggregation on relaxivity of ultra-small dual contrast iron oxide nanoparticles

NASA Astrophysics Data System (ADS)

Ta, Hang T.; Li, Zhen; Wu, Yuao; Cowin, Gary; Zhang, Shaohua; Yago, Anya; Whittaker, Andrew K.; Xu, Zhi Ping

2017-11-01

This study aims to compare the relaxivities of ultra-small dual positive and negative contrast iron oxide nanoparticles (DCION) at different magnetic field strengths ranging from 4.7 to 16.4 T at physiological temperatures; and to investigate the effect of particle aggregation on relaxivities. Relaxivities of DCIONs were determined by magnetic resonance imaging scanners at 4.7, 7, 9.4, and 16.4 T. Both longitudinal (T 1) and transverse relaxation times (T 2) were measured by appropriate spin-echo sequences. It has been found that both longitudinal and transverse relaxivities are significantly dependent on the magnetic field strength. Particle aggregation also strongly affects the relaxivities. Awareness of the field strength and particle colloid stability is crucial for the comparison and evaluation of relaxivity values of these ultra-small iron oxide nanoparticles, and also for their medical applications as contrast agents.

Large density expansion of a hydrodynamic theory for self-propelled particles

NASA Astrophysics Data System (ADS)

Ihle, T.

2015-07-01

Recently, an Enskog-type kinetic theory for Vicsek-type models for self-propelled particles has been proposed [T. Ihle, Phys. Rev. E 83, 030901 (2011)]. This theory is based on an exact equation for a Markov chain in phase space and is not limited to small density. Previously, the hydrodynamic equations were derived from this theory and its transport coefficients were given in terms of infinite series. Here, I show that the transport coefficients take a simple form in the large density limit. This allows me to analytically evaluate the well-known density instability of the polarly ordered phase near the flocking threshold at moderate and large densities. The growth rate of a longitudinal perturbation is calculated and several scaling regimes, including three different power laws, are identified. It is shown that at large densities, the restabilization of the ordered phase at smaller noise is analytically accessible within the range of validity of the hydrodynamic theory. Analytical predictions for the width of the unstable band, the maximum growth rate, and for the wave number below which the instability occurs are given. In particular, the system size below which spatial perturbations of the homogeneous ordered state are stable is predicted to scale with where √ M is the average number of collision partners. The typical time scale until the instability becomes visible is calculated and is proportional to M.

Spontaneous myometrial contractility in cows suffering from endometritis-Influence of localisation, smooth muscle layer and cycle phase. An in vitro study.

PubMed

Hirsbrunner, Gaby; Kaufmann, Ch; Keller, Ch; Hüsler, J; Steiner, A

2010-04-01

Contractility of the healthy bovine myometrium depends on the reproductive state. Furthermore, contractility is influenced by localisation and the direction of smooth muscle strips. However, little is known about the contractile behaviour of the uterus when affected by endometritis. In our study, myometrial specimens from the larger horn (near the corpus and near the tip) in cows suffering from endometritis in estrus (n=8) or diestrus (n=8) were collected after slaughter. Two strips were prepared from each region corresponding to the circular and the longitudinal muscle layers, respectively. The spontaneous contractility of these strips was recorded in an organ bath. To analyse the results, the 2.5h recordings were divided into five periods of 30 min each. The variables area under curve (AUC) and maximal (A(max)) and minimal amplitude (A(min)) were calculated separately for each period, and the results were analysed using a non-parametric model regarding the influence of cycle phase (estrus vs. diestrus), region (corpus vs. tip) and muscle layer (circular vs. longitudinal). The values of both AUC and A(max) increased significantly over time. Muscle layer had a significant effect on AUC (corpus, tip) and A(max) (tip): the values of circular layers were increased compared to longitudinal layers. Dividing the data into subgroups allowed us to analyse them additionally according to muscle layer: In longitudinal layers, A(max) was increased at the corpus as compared with the tip. In this model, the factor cycle phase did not produce any significant difference in spontaneous myometrial activity. However, data of all variables showed non-significant higher values in estrus than in diestrus samples. Copyright 2009 Elsevier B.V. All rights reserved.

Very small IF resonator filters using reflection of shear horizontal wave at free edges of substrate.

PubMed

Kadota, Michio; Ago, Junya; Horiuchi, Hideya; Ikeura, Mamoru

2002-09-01

A shear horizontal (SH) wave has the characteristic of complete reflection at the free edges of a substrate with a large dielectric constant. A conventional surface acoustic wave (SAW) resonator filter requires reflectors consisting of numerous grating fingers on both sides of interdigital transducers (IDTs). On the contrary, it is considered that small-sized and low loss resonator filters without reflectors consisting of grating fingers can be realized by exploiting this characteristic of the SH wave or the Bleustein-Gulyaev-Shimizu (BGS) wave. There are two types of resonator filters: transversely coupled and longitudinally coupled. No transversely coupled filters (neither conventional nor edge-reflection) using the SH wave on a single-crystal substrate have been realized until now, because two transverse modes (symmetrical and asymmetrical modes) are not easily coupled. However, the authors have realized small low loss transversely coupled resonator filters in the range of 25 to 52 MHz using edge reflections of the BGS wave on piezoelectric ceramic (PZT: Pb(Zr,Ti)O3) substrates for the first time by developing methods by which the two transverse modes could be coupled. On the other hand, longitudinally coupled resonator filters using edge reflection of the SH or BGS wave always have large spurious responses because of the even modes in the out-of-band range, because the frequencies of even modes do not coincide with the nulls of the frequency spectra of the IDTs. Consequently, longitudinally coupled resonator filters using the edge reflection of the SH wave have not been realized. By developing a method of reducing the spurious responses without increasing of the insertion loss, the authors have realized small low loss longitudinally coupled resonator filters in the range of 40 to 190 MHz using edge reflection of BGS or SH waves on PZT or 36 degrees-rotated-Y X-propagation LiTaO3 substrates for the first time. Despite being intermediate frequency (IF) filters, their package (3 x 3 x 1.03 mm3) sizes are as small as those of radio frequency (RF) SAW filters.

The Predictive Validity of Four Intelligence Tests for School Grades: A Small Sample Longitudinal Study

PubMed Central

Gygi, Jasmin T.; Hagmann-von Arx, Priska; Schweizer, Florine; Grob, Alexander

2017-01-01

Intelligence is considered the strongest single predictor of scholastic achievement. However, little is known regarding the predictive validity of well-established intelligence tests for school grades. We analyzed the predictive validity of four widely used intelligence tests in German-speaking countries: The Intelligence and Development Scales (IDS), the Reynolds Intellectual Assessment Scales (RIAS), the Snijders-Oomen Nonverbal Intelligence Test (SON-R 6-40), and the Wechsler Intelligence Scale for Children (WISC-IV), which were individually administered to 103 children (Mage = 9.17 years) enrolled in regular school. School grades were collected longitudinally after 3 years (averaged school grades, mathematics, and language) and were available for 54 children (Mage = 11.77 years). All four tests significantly predicted averaged school grades. Furthermore, the IDS and the RIAS predicted both mathematics and language, while the SON-R 6-40 predicted mathematics. The WISC-IV showed no significant association with longitudinal scholastic achievement when mathematics and language were analyzed separately. The results revealed the predictive validity of currently used intelligence tests for longitudinal scholastic achievement in German-speaking countries and support their use in psychological practice, in particular for predicting averaged school grades. However, this conclusion has to be considered as preliminary due to the small sample of children observed. PMID:28348543

The older, the wider: On-field tactical behavior of elite-standard youth soccer players in small-sided games.

PubMed

Olthof, Sigrid B H; Frencken, Wouter G P; Lemmink, Koen A P M

2015-06-01

Young soccer players need excellent tactical skills to reach the top. Tactical behavior emerges through interactions between opposing teams. However, few studies have focused on on-field tactical behavior of teams with talented soccer players. Therefore, this study aimed to determine teams' tactical behavior during small-sided games in two age categories, Under-17 and Under-19. Positional data of thirty-nine elite-standard soccer players were collected during twenty-four small-sided games to calculate longitudinal and lateral inter-team distances, stretch indices and length per width ratios. Corresponding interaction patterns and game-to-game variability were also determined. Under-19 showed a significantly larger lateral stretch index and a significantly lower length per width ratio compared with Under-17. Furthermore, teams of both age groups showed similar large proportions of in-phase behavior. Variability of tactical performance measures within and between games was similar for Under-17 and Under-19. Variability within games seems to be functional for attacking teams for creating goal-scoring opportunities. In conclusion, the main difference was that Under-19 adopted a wider pitch dispersion than Under-17, represented by a larger lateral stretch index and smaller length per width ratio. Coach instructions and training exercises should be directed at exploiting pitch width to increase the pursuit of goal-scoring. Copyright © 2015 Elsevier B.V. All rights reserved.

Calculation of the conductance of two dimensional narrow wires

NASA Astrophysics Data System (ADS)

Kander, Ilan

1989-05-01

There is an interest in the quantum transport of electrons in systems where the sample dimensions are less than a phase coherence length L(sub phi) which is the distance across which the electrons lose phase memory (typically by inelastic scattering). The two-contact conductance is examined of 2-D systems (strips) as functions of Fermi energy system dimensions as is the amount of disorder at zero temperature. Under these conditions all scattering processes are elastic. The term channel is used in order to describe a quantum state with a given transverse quantum number and the appropriate longitudinal momentum. A channel is considered conducting if its longitudinal momentum is real, and decaying if its longitudinal momentum is imaginary. The calculation of the conductance is done in two ways. Transfer matrix for very long systems and Green's function for relatively short ones. The conductance curve in an ordered system is quantized and in a disordered system it is smeared. Interesting changes in the conductance near the thresholds for changes in the quantized value of the conductance are observed.

Tristan performance and plans

NASA Astrophysics Data System (ADS)

Satoh, Kotaro

1992-02-01

This paper summarizes the first phase of the TRISTAN, the energy upgrade for aiming at the energy frontier. Then it describes the present accelerator performance in the second phase where the objective is the luminosity accumulation. The asymmetric B factory is being planned as the third phase of the TRISTAN. This paper also outlines its design and points out some critical issues. These are the longitudinal coupled bunch instability, the chromaticity correction, the insertion design, and injectors.

The g$$p\\atop{2}$$ Experiment: A Measurement of the Proton's Spin Structure Functions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zielinski, Ryan B.

The E08-027 (gmore » $$p\\atop{2}$$) experiment measured the spin structure functions of the proton at Jefferson Laboratory in Newport News, Va. Longitudinally polarized electrons were scattered from a transversely and longitudinally polarized solid ammonia target in Hall A, with the polarized NH$$_3$$ acting as an effective proton target. Focusing on small scattering angle events at the electron energies available at Jefferson Lab, the experiment covered a kinematic phase space of 0.02 GeV$^2$ $< Q^2 <$ 0.20 GeV$^2$ in the proton's resonance region. The spin structure functions, $$g_{1}^p(x,Q^2)$$ and $$g_{2}^p(x,Q^2)$$ , are extracted from an inclusive polarized cross section measurement of the electron-proton interaction. Integrated moments of $$g_1(x,Q^2)$$ are calculated and compared to theoretical predictions made by Chiral Perturbation Theory. The $$g_1(x,Q^2)$$ results are in agreement with previous measurements, but include a significant increase in statistical precision. The spin structure function contributions to the hyperfine energy levels in the hydrogen atom are also investigated. The $$g_2(x,Q^2)$$ measured contribution to the hyperfine splitting is the first ever experimental determination of this quantity. The results of this thesis suggest a disagreement of over 100% with previously published model results.« less

Sound pressure distribution and power flow within the gerbil ear canal from 100 Hz to 80 kHz

PubMed Central

Ravicz, Michael E.; Olson, Elizabeth S.; Rosowski, John J.

2008-01-01

Sound pressure was mapped in the bony ear canal of gerbils during closed-field sound stimulation at frequencies from 0.1 to 80 kHz. A 1.27-mm-diam probe-tube microphone or a 0.17-mm-diam fiber-optic miniature microphone was positioned along approximately longitudinal trajectories within the 2.3-mm-diam ear canal. Substantial spatial variations in sound pressure, sharp minima in magnitude, and half-cycle phase changes occurred at frequencies >30 kHz. The sound frequencies of these transitions increased with decreasing distance from the tympanic membrane (TM). Sound pressure measured orthogonally across the surface of the TM showed only small variations at frequencies below 60 kHz. Hence, the ear canal sound field can be described fairly well as a one-dimensional standing wave pattern. Ear-canal power reflectance estimated from longitudinal spatial variations was roughly constant at 0.2–0.5 at frequencies between 30 and 45 kHz. In contrast, reflectance increased at higher frequencies to at least 0.8 above 60 kHz. Sound pressure was also mapped in a microphone-terminated uniform tube—an “artificial ear.” Comparison with ear canal sound fields suggests that an artificial ear or “artificial cavity calibration” technique may underestimate the in situ sound pressure by 5–15 dB between 40 and 60 kHz. PMID:17902852

Modeling Saturnshine in Cassini Images of the Rings

NASA Astrophysics Data System (ADS)

Dones, Henry C.; Weiss, J. W.; Porco, C. C.; DiNino, D.; Skinner, R.

2013-10-01

In some viewing geometries, such as large solar phase angles or small solar elevation angles, the light reflected by or transmitted through Saturn's rings can be dominated by Saturnshine, i.e., illumination of the rings by the planet. Saturnshine results in longitudinal variations in the reflectivity of the rings. In addition, Saturn's A Ring and, to a lesser extent, B Ring, show intrinsic longitudinal variations ("azimuthal asymmetry") due to self-gravity wakes. Any attempt to infer physical properties of ring particles and their spatial distribution using ring photometry must consider both Saturnshine and self-gravity wakes. "Ringshine," in turn, complicates photometry of Saturn itself [1]. We have improved the Saturnshine model in [2], which applies a ray-tracing code to N-body simulations of a patch of Saturn's rings, by incorporating measurements of the planet's reflectivity in Cassini images taken in a range of viewing geometries through a number of broadband filters. We will compare the results of our photometric model with measurements of the I/F of the main rings, and will attempt to constrain the intrinsic properties of ring particles, such as their coefficients of restitution in collisions and internal densities. We thank the Cassini project for support. [1] Skinner, R.W., and Weiss, J.W. (2011). http://serc.carleton.edu/cismi/undergrad_research/posters/52679.html [2] Porco, C.C., et al. (2008). Astron J. 136, 2172-2200

Studies of longitudinal instability with an electron beam

NASA Astrophysics Data System (ADS)

This progress report covers the research on the 'Study of Longitudinal Instability with an Electron Beam' performed at the University of Maryland during the period from September 1, 1993 to February 28, 1994 of the two-year grant sponsored by the Department of Energy, under Grant No. DEFG02-92ER54178. This research is motivated by the issue of longitudinal instability in induction linacs as drivers for heavy ion inertial fusion. The Fusion Policy Advisory Committee (FPAC) in its final report to DOE (September 1990) identified longitudinal instability as a key physics problem that needs to be solved if an induction linac is to be developed into a successful HIF driver. The FPAC report also stated that 'in parallel' to the design and construction of ILSE 'enhanced theoretical and experimental efforts are required for an improved understanding of potentially serious longitudinal beam instability issues'. The experiment with electron beams in this area is a low-cost way to gain a thorough understanding of the instability and to test computer codes in collaboration with LBL, LLNL, and I. Haber at NRL. The last six months saw the transition of the research activities from phase 1 to phase 2. By the end of last September, the experiments on space-charge waves had been completed. This had fulfilled the first year's goal of this two-year grant. Though the completion of the experiments was one month later than that scheduled and the data analysis still continues up to now, the authors have done much more than was originally proposed.

Electroluminescence pulse shape and electron diffusion in liquid argon measured in a dual-phase TPC

DOE Office of Scientific and Technical Information (OSTI.GOV)

Agnes, P.; et al.

We report the measurement of the longitudinal diffusion constant in liquid argon with the DarkSide-50 dual-phase time projection chamber. The measurement is performed at drift electric fields of 100 V/cm, 150 V/cm, and 200 V/cm using high statisticsmore » $$^{39}$$Ar decays from atmospheric argon. We derive an expression to describe the pulse shape of the electroluminescence signal (S2) in dual-phase TPCs. The derived S2 pulse shape is fit to events from the uppermost portion of the TPC in order to characterize the radial dependence of the signal. The results are provided as inputs to the measurement of the longitudinal diffusion constant DL, which we find to be (4.12 $$\\pm$$ 0.04) cm$^2$/s for a selection of 140keV electron recoil events in 200V/cm drift field and 2.8kV/cm extraction field. To study the systematics of our measurement we examine datasets of varying event energy, field strength, and detector volume yielding a weighted average value for the diffusion constant of (4.09 $$\\pm$$ 0.09) cm$^2$ /s. The measured longitudinal diffusion constant is observed to have an energy dependence, and within the studied energy range the result is systematically lower than other results in the literature.« less

Morphometric Study of the Mare Oviductal Mucosa at Different Reproductive Stages.

PubMed

Mouguelar, Horacio; Díaz, Tomás; Borghi, Damiana; Quinteros, Rolando; Bonino, Facundo; Apichela, Silvana Andrea; Aguilar, José Javier

2015-11-01

The objectives of this work were to describe some morphometric characteristics and to establish quantitative parameters of different regions of the equine oviductal mucosa from the isthmus, ampullary-isthmic junction (AIJ), and ampulla. Twenty-one mixed-bred mares were used for this study. Mares were selected in the following reproductive phases: anestrus, estrus, and diestrus. The left oviducts were examined with light microscopy, and rights ones were studied through the intraoviductal molds. The isthmus showed the smallest luminal area, mucosal area, epithelial perimeter, and luminal diameter. On the molds surfaces, some grooves extended as longitudinal canals, reducing their depth as they approached to the AIJ. Several small height projections, some obliquely positioned towards utero-tubal junction, were observed in all reproductive phases. These formations may represent pockets or cul-de-sacs in the basal areas of the epithelial folds. The AIJ mucosa gradually changed from the smooth isthmic region toward highly folded ampulla. The number and complexity of epithelial folds showed moderate increase in the same way that many of the morphometric parameters. Multiple curves were observed on the molds of the AIJ, creating a zigzag path in the oviductal lumen. In the ampulla, the high branched epithelial folds occupied most of the lumen, leaving a small luminal area free. A linear relationship between epithelial perimeter and mucosal area was found. The presence of glandular-like structures was observed in all the reproductive stages studied. The equine endosalpinx reveals a highly complex tridimensional arrangement where each region shows very particular and specific designs. © 2015 Wiley Periodicals, Inc.

Advances in Studies of Electrode Kinetics and Mass Transport in AMTEC Cells (abstract)

NASA Technical Reports Server (NTRS)

Williams, R. M.; Jeffries-Nakamura, B.; Ryan, M. A.; Underwood, M. L.; Kisor, A.; O'Connor, D.; Kikkert, S.

1993-01-01

Previous work reported from JPL has included characterization of electrode kinetics and alkali atom transport from electrodes including Mo, W, WRh(sub x), WPt(sub x)(Mn), in sodium AMTEC cells and vapor exposure cells, and Mo in potassium vapor exposure cells. These studies were generally performed in cells with small area electrodes (about 1 to 5 cm(sup 2)), and device geometry had little effect on transport. Alkali diffusion coefficients through these electrodes have been characterized, and approximate surface diffusion coefficients derived in cases of activated transport. A basic model of electrode kinetic at the alkali metal vapor/porous metal electrode/alkali beta'-alumina solid electrolyte three phase boundary has been proposed which accounts for electrochemical reaction rates with a collision frequency near the three phase boundary and tunneling from the porous electrode partially covered with adsorbed alkali metal atoms. The small electrode effect in AMTEC cells has been discussed in several papers, but quantitative investigations have described only the overall effect and the important contribution of electrolyte resistance. The quantitative characterization of transport losses in cells with large area electrodes has been limited to simulations of large area electrode effects, or characterization of transport losses from large area electrodes with significant longitudinal temperature gradients. This paper describes new investigations of electrochemical kinetics and transport, particularily with WPt(sub 3.5) electrodes, including the influence of electrode size on the mass transport loss in the AMTEC cell. These electrodes possess excellent sodium transport properties making verification of device limitations on transport much more readily attained.

The effects of small-scale, homelike facilities for older people with dementia on residents, family caregivers and staff: design of a longitudinal, quasi-experimental study.

PubMed

Verbeek, Hilde; van Rossum, Erik; Zwakhalen, Sandra M G; Ambergen, Ton; Kempen, Gertrudis I J M; Hamers, Jan P H

2009-01-20

Small-scale and homelike facilities for older people with dementia are rising in current dementia care. In these facilities, a small number of residents live together and form a household with staff. Normal, daily life and social participation are emphasized. It is expected that these facilities improve residents' quality of life. Moreover, it may have a positive influence on staff's job satisfaction and families involvement and satisfaction with care. However, effects of these small-scale and homelike facilities have hardly been investigated. Since the number of people with dementia increases, and institutional long-term care is more and more organized in small-scale and homelike facilities, more research into effects is necessary. This paper presents the design of a study investigating effects of small-scale living facilities in the Netherlands on residents, family caregivers and nursing staff. A longitudinal, quasi-experimental study is carried out, in which 2 dementia care settings are compared: small-scale living facilities and regular psychogeriatric wards in traditional nursing homes. Data is collected from residents, their family caregivers and nursing staff at baseline and after 6 and 12 months of follow-up. Approximately 2 weeks prior to baseline measurement, residents are screened on cognition and activities of daily living (ADL). Based on this screening profile, residents in psychogeriatric wards are matched to residents living in small-scale living facilities. The primary outcome measure for residents is quality of life. In addition, neuropsychiatric symptoms, depressive symptoms and social engagement are assessed. Involvement with care, perceived burden and satisfaction with care provision are primary outcome variables for family caregivers. The primary outcomes for nursing staff are job satisfaction and motivation. Furthermore, job characteristics social support, autonomy and workload are measured. A process evaluation is performed to investigate to what extent small-scale living facilities and psychogeriatric wards are designed as they were intended. In addition, participants' satisfaction and experiences with small-scale living facilities are investigated. A longitudinal, quasi-experimental study is presented to investigate effects of small-scale living facilities. Although some challenges concerning this design exist, it is currently the most feasible method to assess effects of this relatively new dementia care setting.

Flowing together: a longitudinal study of collective efficacy and collective flow among workgroups.

PubMed

Salanova, Marisa; Rodríguez-Sánchez, Alma M; Schaufeli, Wilmar B; Cifre, Eva

2014-01-01

The aim of this study is to extend the Channel Model of Flow (Csikszentmihalyi, 1975, 1990) at the collective level (workgroups) by including collective efficacy beliefs as a predictor of collective flow based on the Social Cognitive Theory (Bandura, 1997, 2001). A two-wave longitudinal lab study was conducted with 250 participants working in 52 small groups. Longitudinal results from Structural Equation Modeling with data aggregated at the group level showed, as expected, that collective efficacy beliefs predict collective flow over time, both being related reciprocally. Findings and their theoretical and practical implications in the light of Social Cognitive Theory are discussed.

An analysis of the effects of aeroelasticity on static longitudinal stability and control of a swept-back-wing airplane

NASA Technical Reports Server (NTRS)

Skoog, Richard B

1951-01-01

A theoretical analysis of the effects of aeroelasticity on the stick-fixed static longitudinal stability and elevator angle required for balance of an airplane is presented together with calculated effects for a swept-wing bomber of relatively high flexibility. Although large changes in stability due to certain parameters are indicated for the example airplane, the over-all stability change after considering all parameters was quite small, compared to the individual effects, due to the counterbalancing of wing and tail contributions. The effect of flexibility on longitudinal control for the example airplane was found to be of little real importance.

Analysis of the proton longitudinal structure function from the gluon distribution function

NASA Astrophysics Data System (ADS)

Boroun, G. R.; Rezaei, B.

2012-11-01

We make a critical, next-to-leading order, study of the relationship between the longitudinal structure function F L and the gluon distribution proposed in Cooper-Sarkar et al. (Z. Phys. C 39:281, 1988; Acta Phys. Pol. B 34:2911 2003), which is frequently used to extract the gluon distribution from the proton longitudinal structure function at small x. The gluon density is obtained by expanding at particular choices of the point of expansion and compared with the hard Pomeron behavior for the gluon density. Comparisons with H1 data are made and predictions for the proposed best approach are also provided.

76 FR 6478 - Revision to Proposed Collection; Comment Request; The National Children's Study (NCS), Vanguard...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-02-04

...: The purpose of the proposed methodological study is to continue the Vanguard phase of the National... study design elements for a prospective, national longitudinal study of child health and development. In combination, the sub-studies encompassed by the Vanguard Phase will be used to inform the design of the Main...

Small Business Innovation Research GRC Phase I, Phase II, and Post-Phase II Opportunity Assessment for 2015

NASA Technical Reports Server (NTRS)

Nguyen, Hung D.; Steele, Gynelle C.

2016-01-01

This report outlines the 2015 Small Business Innovation Research/Small Business Technology Transfer (SBIR/STTR) Phase I, Phase II, and Post-Phase II opportunity contract award results associated with NASA's Aeronautics Research Mission Directorate (ARMD), Human Exploration and Operations Mission Directorate (HEOMD), Science Mission Directorate (SMD), and Space Technology Mission Directorate (STMD) for NASA Glenn Research Center. The report also highlights the number of Phase I, Phase II, and Post-Phase II contracts awarded by mission directorate. The 2015 Phase I contract awards to companies in Ohio and their corresponding technologies are also discussed.

Asymptotic formulae for flow in superhydrophobic channels with longitudinal ridges and protruding menisci

NASA Astrophysics Data System (ADS)

Kirk, Toby L.

2018-03-01

This paper presents new analytical formulae for flow in a channel with one or both walls patterned with a longitudinal array of ridges and arbitrarily protruding menisci. Derived from a matched asymptotic expansion, they extend results by Crowdy (J. Fluid Mech., vol. 791, 2016, R7) for shear flow, and thus make no restriction on the protrusion into or out of the liquid. The slip length formula is compared against full numerical solutions and, despite the assumption of small ridge period in its derivation, is found to have a very large range of validity; relative errors are small even for periods large enough for the protruding menisci to degrade the flow and touch the opposing wall.

The Impact of Changes in the TOEFL® Exam on Teaching in a Sample of Countries in Europe: Phase 3, The Role of the Coursebook; Phase 4, Describing Change. TOEFL iBT® Research Report. TOEFL iBT-17. ETS Research Report. RR-11-41

ERIC Educational Resources Information Center

Wall, Dianne; Horák, Tania

2011-01-01

The aim of this report is to present the findings of the 3rd and 4th phases of a longitudinal study into the impact of changes in the TOEFL® exam on teaching in test preparation classrooms. Phase 1 (2003-2004) described the type of teaching taking place in 12 TOEFL preparation classrooms before the introduction of the new TOEFL. Phase 2…

STUDYING ATMOSPHERE-DOMINATED HOT JUPITER KEPLER PHASE CURVES: EVIDENCE THAT INHOMOGENEOUS ATMOSPHERIC REFLECTION IS COMMON

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shporer, Avi; Hu, Renyu

2015-10-15

We identify three Kepler transiting planets, Kepler-7b, Kepler-12b, and Kepler-41b, whose orbital phase-folded light curves are dominated by planetary atmospheric processes including thermal emission and reflected light, while the impact of non-atmospheric (i.e., gravitational) processes, including beaming (Doppler boosting) and tidal ellipsoidal distortion, is negligible. Therefore, those systems allow a direct view of their atmospheres without being hampered by the approximations used in the inclusion of both atmospheric and non-atmospheric processes when modeling the phase-curve shape. We present here the analysis of Kepler-12b and Kepler-41b atmosphere based on their Kepler phase curve, while the analysis of Kepler-7b was already presentedmore » elsewhere. The model we used efficiently computes reflection and thermal emission contributions to the phase curve, including inhomogeneous atmospheric reflection due to longitudinally varying cloud coverage. We confirm Kepler-12b and Kepler-41b show a westward phase shift between the brightest region on the planetary surface and the substellar point, similar to Kepler-7b. We find that reflective clouds located on the west side of the substellar point can explain the phase shift. The existence of inhomogeneous atmospheric reflection in all three of our targets, selected due to their atmosphere-dominated Kepler phase curve, suggests this phenomenon is common. Therefore, it is also likely to be present in planetary phase curves that do not allow a direct view of the planetary atmosphere as they contain additional orbital processes. We discuss the implications of a bright-spot shift on the analysis of phase curves where both atmospheric and gravitational processes appear, including the mass discrepancy seen in some cases between the companion’s mass derived from the beaming and ellipsoidal photometric amplitudes. Finally, we discuss the potential detection of non-transiting but otherwise similar planets, whose mass is too small to show a gravitational photometric signal, but their atmosphere is reflective enough to show detectable phase modulations.« less

A Longitudinal Study of Social Relationships and Networks in the Transition to and within Adulthood for Vulnerable Young Adults at Ages 24, 29 and 34 Years: Compensation, Reinforcement or Cumulative Disadvantages?

ERIC Educational Resources Information Center

Bele, Irene Velsvik; Kvalsund, Rune

2016-01-01

This longitudinal study, spanning from 1995 through 2012, followed vulnerable youth from upper secondary school (T1) as they made the transition to their early twenties (T2), late twenties (T3) and mid-thirties (T4). We investigated their social network relationships in different phases of adult life, focusing mainly on factors that explain…

Associations of Parenting Dimensions and Styles with Externalizing Problems of Children and Adolescents: An Updated Meta-Analysis

ERIC Educational Resources Information Center

Pinquart, Martin

2017-01-01

The present meta-analysis integrates research from 1,435 studies on associations of parenting dimensions and styles with externalizing symptoms in children and adolescents. Parental warmth, behavioral control, autonomy granting, and an authoritative parenting style showed very small to small negative concurrent and longitudinal associations with…

Plasma generators, reactor systems and related methods

DOEpatents

Kong, Peter C [Idaho Falls, ID; Pink, Robert J [Pocatello, ID; Lee, James E [Idaho Falls, ID

2007-06-19

A plasma generator, reactor and associated systems and methods are provided in accordance with the present invention. A plasma reactor may include multiple sections or modules which are removably coupled together to form a chamber. Associated with each section is an electrode set including three electrodes with each electrode being coupled to a single phase of a three-phase alternating current (AC) power supply. The electrodes are disposed about a longitudinal centerline of the chamber and are arranged to provide and extended arc and generate an extended body of plasma. The electrodes are displaceable relative to the longitudinal centerline of the chamber. A control system may be utilized so as to automatically displace the electrodes and define an electrode gap responsive to measure voltage or current levels of the associated power supply.

Investigation of individual and group variability in estrous cycle characteristics in female Asian elephants (Elephas maximus) at the Oregon Zoo.

PubMed

Glaeser, S S; Hunt, K E; Martin, M S; Finnegan, M; Brown, J L

2012-07-15

Evaluating ovarian cycle activity through longitudinal progestagen monitoring is important for optimizing breeding management of captive elephants and understanding impact of life events (births, deaths, and transfers) on reproductive function. This study summarized serum progestagen profiles for eight Asian mainland elephants (Elephas maximus indicus) and one Bornean elephant (E. maximus borneensis) at the Oregon Zoo over a 20-yr interval, and represents the longest longitudinal dataset evaluated to date. Estrous cycle characteristics were more varied than previously reported for this species, with an overall duration of 12 to 19 wk, luteal phase duration of 4 to 15 wk, and follicular phase duration of 2 to 12 wk. In general, there was more cycle variability across than within individual elephants. Compared with other elephants in the group, the Borneo female exhibited consistently longer cycle lengths, higher progestagen concentrations, and greater cycle variability; however, it is not known if this represents a subspecies or an individual difference. Cycle durations did not appear to change over time or with age, and the first pubertal cycle was similar to subsequent cycles. Variability in duration of the follicular phase was greater than that of the luteal phase. In addition, there was a significant negative relationship between luteal and follicular phase durations, suggesting a possible regulatory role of the follicular phase in maintaining a relatively consistent cycle duration within individuals. Overall, we found these elephants to be highly resilient in that major life events (births, deaths, and changes in herd structure) had minimal effect on cycle dynamics over time. In conclusion, the higher range in cycle phase characteristics is likely because of the larger number of elephants studied and longer duration of longitudinal monitoring, and may be more representative of the captive population as a whole. Furthermore, identification of significant interanimal variability suggests that understanding the complexities of herd reproductive characteristics could facilitate development of more effective institution-specific breeding management strategies. Copyright © 2012 Elsevier Inc. All rights reserved.

Method for measuring liquid viscosity and ultrasonic viscometer

DOEpatents

Sheen, Shuh-Haw; Lawrence, William P.; Chien, Hual-Te; Raptis, Apostolos C.

1994-01-01

An ultrasonic viscometer and method for measuring fluid viscosity are provided. Ultrasonic shear and longitudinal waves are generated and coupled to the fluid. Reflections from the generated ultrasonic shear and longitudinal waves are detected. Phase velocity of the fluid is determined responsive to the detected ultrasonic longitudinal waves reflections. Viscosity of the fluid is determined responsive to the detected ultrasonic shear waves reflections. Unique features of the ultrasonic viscometer include the use of a two-interface fluid and air transducer wedge to measure relative signal change and to enable self calibration and the use of a ratio of reflection coefficients for two different frequencies to compensate for environmental changes, such as temperature.

Micro-CT Based Experimental Liver Imaging Using a Nanoparticulate Contrast Agent: A Longitudinal Study in Mice

PubMed Central

Boll, Hanne; Nittka, Stefanie; Doyon, Fabian; Neumaier, Michael; Marx, Alexander; Kramer, Martin; Groden, Christoph; Brockmann, Marc A.

2011-01-01

Background Micro-CT imaging of liver disease in mice relies on high soft tissue contrast to detect small lesions like liver metastases. Purpose of this study was to characterize the localization and time course of contrast enhancement of a nanoparticular alkaline earth metal-based contrast agent (VISCOVER ExiTron nano) developed for small animal liver CT imaging. Methodology ExiTron nano 6000 and ExiTron nano 12000, formulated for liver/spleen imaging and angiography, respectively, were intravenously injected in C57BL/6J-mice. The distribution and time course of contrast enhancement were analysed by repeated micro-CT up to 6 months. Finally, mice developing liver metastases after intrasplenic injection of colon carcinoma cells underwent longitudinal micro-CT imaging after a single injection of ExiTron nano. Principal Findings After a single injection of ExiTron nano the contrast of liver and spleen peaked after 4–8 hours, lasted up to several months and was tolerated well by all mice. In addition, strong contrast enhancement of abdominal and mediastinal lymph nodes and the adrenal glands was observed. Within the first two hours after injection, particularly ExiTron nano 12000 provided pronounced contrast for imaging of vascular structures. ExiTron nano facilitated detection of liver metastases and provided sufficient contrast for longitudinal observation of tumor development over weeks. Conclusions The nanoparticulate contrast agents ExiTron nano 6000 and 12000 provide strong contrast of the liver, spleen, lymph nodes and adrenal glands up to weeks, hereby allowing longitudinal monitoring of pathological processes of these organs in small animals, with ExiTron nano 12000 being particularly optimized for angiography due to its very high initial vessel contrast. PMID:21984939

Transverse and longitudinal tensile properties at 760 C of several oxide dispersion strengthened nickel-base alloys

NASA Technical Reports Server (NTRS)

Anglin, A. E., Jr.

1979-01-01

The transverse and longitudinal tensile properties of the oxide dispersion strengthened nickel-base alloys were determined at 760 C. The alloys with small amounts of gamma prime have strength levels suitable for turbine vane applications, while other highly alloyed, gamma prime strengthened superalloys have strengths typical of turbine blade materials. These alloys were produced by mechanical alloying and extrusion and the turbine blade alloys were also directionally recrystallized. Resultant grain aspect ratios varied from 1:1 to over 20:1. Longitudinal tensile strengths ranged from 285 to 1175 MPa, while longitudinal elongations were in excess of 4 percent for all alloys. Transverse tensile strengths were comparable to longitudinal strengths, but transverse ductility levels were generally less than 2 percent elongation. Tensile and yield strengths increased with increasing strain rate over the range 0.001 to 0.05 per second. Ductility in both orientations was not strain rate sensitive but could be related to grain size and grain aspect ratio.

Static Longitudinal Stability and Control Characteristics At A Mach Number of 1.99 of a Lenticular-Shaped Reentry Vehicle

NASA Technical Reports Server (NTRS)

Jackson, Charles M., Jr.; Harris, Roy V., Jr.

1960-01-01

An investigation has been made in the Langley 4- by 4-foot supersonic pressure tunnel at a Mach number of 1.99 to determine the longitudinal stability and control characteristics of a reentry model consisting of a lenticular-shaped body with two fin configurations (horizontal fins with end plates). Effects of deflecting the larger size fins as pitch-control surfaces were also investigated. The results indicate that the body alone was unstable from an angle of attack of 0 deg to about 55 deg where it became stable and remained so to 90 deg. The addition of fins provided positive longitudinal stability throughout the angle-of-attack range and increased the lift-drag ratio of the configuration. Reducing the horizontal-fin area at the inboard trailing edge of the fin had only a small effect on the aerodynamic characteristics of the vehicle for the condition of no fin deflection. Deflecting the fins, appeared to be an effective means of pitch control and had only a small effect on lift-drag ratio.

Wind-Tunnel Investigation of the Static Longitudinal Stability Characteristics of a 0.15-Scale Model of the Hermes A-1E2 Missile at High Subsonic Mach Numbers

NASA Technical Reports Server (NTRS)

Alford, William J., Jr.

1952-01-01

The static longitudinal stability characteristics of a 0.15-scale model of the Hermes A-lE2 missile have been determined in the Langley high-speed 7- by 10-foot tunnel over a Mach number range of 0.50 to 0.98, corresponding to Reynolds numbers, based on body length, of 12.3 x 10(exp 6) to 17.1 x 10(exp 6). This paper presents results obtained with body alone and body-fins combinations at 0 degrees (one set of fins vertical and the other set horizontal) and 45 degree angle of roll. The results indicate that the addition of the fins to the body insures static longitudinal stability and provides essentially linear variations of the lift and pitching moment at small angles of attack throughout the Mach number range. The slopes of the lift and pitching-moment curves vary slightly with Mach number and show only small effects due to the angle of roll.

Longitudinal in vivo transcutaneous observation of Raman signals from breast cancer during chemotherapy in small animal model

NASA Astrophysics Data System (ADS)

Seong, Myeongsu; Myoung, NoSoung; Yim, Sang-Youp; Kim, Jae G.

2015-02-01

Because mammography, the gold standard of breast cancer screening and monitoring treatment efficacy, has limitations, there is a necessity to have a new method for breast cancer patients. Raman spectroscopy is considered as one of the best alternative approaches due to its ability of visualizing (bio)chemical information of a matter. In this study, we hypothesized that the change of biochemical composition occurs earlier than morphological change in breast cancer during chemotherapy, and attempted to prove it by employing fiber-optic Raman spectroscopy for longitudinal Raman measurement in small animal breast cancer model. To confirm the hypothesis, we measured Raman spectra of a tumor breast and the contralateral breast during chemotherapy for 4 fisher 344 female rats longitudinally. Principal component analysis and Raman spectral differences between breast tumor and contralateral normal breast did not show a clear difference between them which may have been caused by interference from skin. Thus, spatially-offset Raman spectroscopy will be employed in order to acquire the Raman signal directly from tumor while suppressing Raman signal from skin for the future study.

The implication of non-cyclic intrafractional longitudinal motion in SBRT by TomoTherapy

NASA Astrophysics Data System (ADS)

Yang, Wensha; Van Ausdal, Ray; Read, Paul; Larner, James; Benedict, Stan; Sheng, Ke

2009-05-01

To determine the dosimetric impact of non-cyclic longitudinal intrafractional motion, TomoTherapy plans with different field sizes were interrupted during a phantom delivery, and a displacement between -5 mm and 5 mm was induced prior to the delivery of the completion procedure. The planar dose was measured by film and a cylindrical phantom, and under-dosed or over-dosed volume was observed for either positive or negative displacement. For a 2.5 cm field, there was a 4% deviation for every mm of motion and for a 1 cm field, the deviation was 8% per mm. The dimension of the under/over-dosed area was independent of the motion but dependent on the field size. The results have significant implication in small-field high-dose treatments (i.e. stereotactic body radiation therapy (SBRT)) that deliver doses in only a few fractions. Our studies demonstrate that a small longitudinal motion may cause a dose error that is difficult to compensate; however, dividing a SBRT fraction into smaller passes is helpful to reduce such adverse effects.

Anticipated Job Benefits, Career Aspiration, and Generalized Self-efficacy as Predictors for Migration Decision-Making

PubMed Central

Hoppe, Annekatrin; Fujishiro, Kaori

2015-01-01

This study aims to identify person-level factors, rather than economic situations, that influence migration decision-making and actual migration. Building on the theory of planned behavior, this study investigated potential migrants’ expectations and attitudes toward migration and career (i.e., anticipated job benefits of migration, career aspiration) as well as beliefs (i.e., generalized self-efficacy) as predictors of migration decision-making conceptualized in three phases: the pre-decisional, pre-actional, and actional phases. This was examined with cross-sectional pre-migration questionnaire data from 1163 potential migrants from Spain to Germany. We also examined whether the migration decision-making phases predicted actual migration with a subsample (n=249) which provided follow-up data within twelve months. For the cross-sectional sample, multinomial logistic regressions revealed that anticipated job benefits and career aspiration are predictive for all migration phases. Self-efficacy predicts the preactional (e.g., gathering information) and actional phases (e.g., making practical arrangements). Finally, for those with low self-efficacy, anticipated job benefits play a stronger role for taking action. For the longitudinal subsample, a logistic regression revealed that being in the preactional and actional phases at baseline is predictive of actual migration within twelve months. This study expands previous research on migration intentions and behaviors by focusing on expectations, values, and beliefs as person-level predictors for migration decision-making. With a longitudinal sample, it shows that international migration is a process that involves multiple phases. PMID:26379343

The Project P.A.T.H.S. in Hong Kong: Work Done and Lessons Learned in a Decade.

PubMed

Shek, Daniel T L; Wu, Florence K Y

2016-02-01

The Project Positive Adolescent Training through Holistic Social Programs is a positive youth development program initiated and financially supported by The Hong Kong Jockey Club Charities Trust. Since 2005, the project has gone through several phases, including the initial phase (2005-2012), school-based extension phase (2009-2016), and community-based extension phase (2013-2017). In the initial phase, with the involvement of academics from 5 universities in Hong Kong, the research team developed youth enhancement programs for junior secondary school students (20 hours per grade), trained the program implementers (20 hours per grade), assisted in the implementation in more than 250 schools, and evaluated the program using multiple evaluation strategies, including a 5-year longitudinal experimental study. In the school-based extension phase, the project was implemented for another cycle (2009-2010 and 2011-2012 school years) and a 6-year longitudinal study was conducted to understand the psychosocial development of Chinese adolescents in Hong Kong. In the community-based extension phase, the programs were administered by social workers in the community settings. Generally speaking, different evaluation findings showed that the programs in Project Positive Adolescent Training through Holistic Social Programs promoted positive development and reduced risk behavior in Chinese adolescents in Hong Kong. Positive youth development attributes and family functioning also have positive contributions to adolescent developmental outcomes over time. Copyright © 2016 North American Society for Pediatric and Adolescent Gynecology. Published by Elsevier Inc. All rights reserved.

Successful minority recruitment and adherence in physical activity Internet-based research: the WIN study.

PubMed

Frierson, Georita M; Morrow, James R; Vidales, Andrew

2012-01-01

Researchers studying physical activity often face challenges dealing with recruitment and resources, particularly when conducting longitudinal Internet-based research. Commonly raised methodological problems such as minority recruitment, participant commitment, and participant-staff involvement are addressed through a theoretically driven recruitment and adherence protocol in The Women's Exercise Injuries: Incidence and Risk Factors (WIN) Internet-based study. The objectives of this paper were to review and suggest solutions to problems of: (1) low recruitment of diverse samples, (2) low adherence, and (3) staffing needs. We recruited 1303 community-dwelling women and followed them through a multiple-phase, longitudinal, Internet-based study. Recruitment and adherence data were analyzed through descriptive methods and logistic regressions to examine participant adherence and sociodemographic factors and predictors of who entered the long-term phase of the study. We successfully retained 71.6% of the sample through 4 recruitment phases. Twenty-seven percent of the initially recruited sample was racial/ethnically diverse, 24% began the long-term phase, and 23% completed. Several strategies to enhance participant commitment were successfully used during the practice phase, providing a successful, low staff to participant ratio. Logistic regression indicated being married, being older, and having greater Internet skills were predictive of successfully entering the long-term phase of the study. Recruitment and compliance protocols were successful in meeting overall and racial/ethnic enrollment and recruitment goals. The theoretically based practice phase techniques were successful in re-engaging noncompliant participants. Strategies for minority enrollment and compliance are evaluated.

Dancing bunches as Van Kampen modes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Burov, A.; /Fermilab

2011-03-01

Van Kampen modes are eigen-modes of Jeans-Vlasov equation [1-3]. Their spectrum consists of continuous and, possibly, discrete parts. Onset of a discrete van Kampen mode means emergence of a coherent mode without any Landau damping; thus, even a tiny couple-bunch wake is sufficient to drive instability. Longitudinal instabilities observed at Tevatron [4], RHIC [5] and SPS [6] can be explained as loss of Landau damping (LLD), which is shown here to happen at fairly low impedances. For repulsive wakes and single-harmonic RF, LLD is found to be extremely sensitive to steepness of the bunch distribution function at small amplitudes. Basedmore » on that, a method of beam stabilization is suggested. Emergence of a discrete van Kampen mode means either loss of Landau damping or instability. Longitudinal bunch stability is analysed in weak head-tail approximation for inductive impedance and single-harmonic RF. The LLD threshold intensities are found to be rather low: for cases under study all of them do not exceed a few percent of the zero-amplitude incoherent synchrotron frequency shift, strongly decreasing for shorter bunches. Because of that, LLD can explain longitudinal instabilities happened at fairly low impedances at Tevatron [4], and possibly for RHIC [5] and SPS [6], being in that sense an alternative to the soliton explanation [5, 20]. Although LLD itself results in many cases in emergence of a mode with zero growth rate, any couple-bunch (and sometimes multi-turn) wake would drive instability for that mode, however small this wake is. LLD is similar to a loss of immune system of a living cell, when any microbe becomes fatal for it. The emerging discrete mode is normally very different from the rigid-bunch motion; thus the rigid-mode model significantly overestimates the LLD threshold. The power low of LLD predicted in Ref. [17] agrees with results of this paper. However, the numerical factor in that scaling low strongly depends on the bunch distribution function. Particularly, for inductive impedance above transition and three examined distributions, the highest LLD threshold intensity exceeds the lowest one by a factor of {approx}100. Based on that observation, proper RF phase shaking as a method of beam stabilization is suggested.« less

Nonmedical Drug Use among University Students -- 1967-1970.

ERIC Educational Resources Information Center

Dvorak, Edward J.; Rupprecht, Paul

This report is a summary of a longitudinal study of nonmedical drug use among university students which was carried out by members of the staff of the University of Minnesota Health Service. The study was conducted in 2 phases. The subjects in the first phase of the study were students who registered for the first time at the University of…

A two-step method for retrieving the longitudinal profile of an electron bunch from its coherent radiation

NASA Astrophysics Data System (ADS)

Pelliccia, Daniele; Sen, Tanaji

2014-11-01

The coherent radiation emitted by an electron bunch provides a diagnostic signal that can be used to estimate its longitudinal distribution. Commonly only the amplitude of the intensity spectrum can be measured and the associated phase must be calculated to obtain the bunch profile. Very recently an iterative method was proposed to retrieve this phase. However ambiguities associated with non-uniqueness of the solution are always present in the phase retrieval procedure. Here we present a method to overcome the ambiguity problem by first performing multiple independent runs of the phase retrieval procedure and then second, sorting the good solutions by means of cross-correlation analysis. Results obtained with simulated bunches of various shapes and experimental measured spectra are presented, discussed and compared with the established Kramers-Kronig method. It is shown that even when the effect of the ambiguities is strong, as is the case for a double peak in the profile, the cross-correlation post-processing is able to filter out unwanted solutions. We show that, unlike the Kramers-Kronig method, the combined approach presented is able to faithfully reconstruct complicated bunch profiles.

Interpersonal dynamics and relative positioning to scoring target of performers in 1 vs. 1 sub-phases of team sports.

PubMed

Esteves, Pedro T; Araújo, Duarte; Davids, Keith; Vilar, Luís; Travassos, Bruno; Esteves, Carlos

2012-01-01

In this study, we examined the effects of relative positioning of attacker-defender dyads to the basket on interpersonal coordination tendencies in basketball. To achieve this aim, four right-hand dominant basketball players performed in a 1 vs. 1 sub-phase, at nine different playing locations relative to the basket (from 0° to 180°, in 20° increments). Performers' movement displacement trajectories were video-recorded and digitized in 162 trials. Results showed that interpersonal coordination tendencies changed according to the scaling of the relative position of performers to the basket. Stable in-phase modes of coordination were observed between performers' longitudinal and lateral displacements (50.47% and 43.02%) on the left side of the court. On the right side of the court, a shift in the dominant mode of coordination was observed to a defender lead-lag of -30°, both for longitudinal and lateral displacements (30.51% and 32.65%). These results suggest how information about dribbler hand dominance and relative position to the basket may have constrained attacker-defender coordination tendencies in 1 vs. 1 sub-phases of basketball.

Evolution of the electrical resistivity anisotropy during saline tracer tests: insights from geoelectrical milli-fluidic experiments

NASA Astrophysics Data System (ADS)

Jougnot, D.; Jimenez-Martinez, J.; Legendre, R.; Le Borgne, T.; Meheust, Y.; Linde, N.

2017-12-01

The use of time-lapse electrical resistivity tomography has been largely developed in environmental studies to remotely monitor water saturation and contaminant plumes migration. However, subsurface heterogeneities, and corresponding preferential transport paths, yield a potentially large anisotropy in the electrical properties of the subsurface. In order to study this effect, we have used a newly developed geoelectrical milli-fluidic experimental set-up with a flow cell that contains a 2D porous medium consisting of a single layer of cylindrical solid grains. We performed saline tracer tests under full and partial water saturations in that cell by jointly injecting air and aqueous solutions with different salinities. The flow cell is equipped with four electrodes to measure the bulk electrical resistivity at the cell's scale. The spatial distribution of the water/air phases and the saline solute concentration field in the water phase are captured simultaneously with a high-resolution camera by combining a fluorescent tracer with the saline solute. These data are used to compute the longitudinal and transverse effective electrical resistivity numerically from the measured spatial distributions of the fluid phases and the salinity field. This approach is validated as the computed longitudinal effective resistivities are in good agreement with the laboratory measurements. The anisotropy in electrical resistivity is then inferred from the computed longitudinal and transverse effective resistivities. We find that the spatial distribution of saline tracer, and potentially air phase, drive temporal changes in the effective resistivity through preferential paths or barriers for electrical current at the pore scale. The resulting heterogeneities in the solute concentrations lead to strong anisotropy of the effective bulk electrical resistivity, especially for partially saturated conditions. Therefore, considering the electrical resistivity as a tensor could improve our understanding of transport properties from field-scale time-lapse ERT.

Associations between onset of effort-reward imbalance at work and onset of musculoskeletal pain: analyzing observational longitudinal data as pseudo-trials.

PubMed

Halonen, Jaana I; Virtanen, Marianna; Leineweber, Constanze; Rod, Naja H; Westerlund, Hugo; Magnusson Hanson, Linda L

2018-03-27

Existing evidence of an association between effort-reward imbalance (ERI) at work and musculoskeletal pain is limited, preventing reliable conclusions about the magnitude and direction of the relation. In a large longitudinal study, we examined whether the onset of ERI is associated with subsequent onset of musculoskeletal pain among those free of pain at baseline, and vice versa, whether onset of pain leads to onset of ERI. Data were from the Swedish Longitudinal Occupational Survey of Health (SLOSH) study. We used responses from 3 consecutive study phases to examine whether exposure onset between the first and second phases predicts onset of the outcome in the third phase (N = 4079). Effort-reward imbalance was assessed with a short form of the ERI model. Having neck-shoulder and low back pain affecting life to some degree in the past 3 months was also assessed in all study phases. As covariates, we included age, sex, marital status, occupational status, and physically strenuous work. In the adjusted models, onset of ERI was associated with onset of neck-shoulder pain (relative risk [RR] 1.51, 95% confidence interval [CI] 1.21-1.89) and low back pain (RR 1.21, 95% CI 0.97-1.50). The opposite was also observed, as onset of neck-shoulder pain increased the risk of subsequent onset of ERI (RR 1.36, 95% CI 1.05-1.74). Our findings suggest that when accounting for the temporal order, the associations between ERI and musculoskeletal pain that affects life are bidirectional, implying that interventions to both ERI and pain may be worthwhile to prevent a vicious cycle.

Shapiro steps for skyrmion motion on a washboard potential with longitudinal and transverse ac drives

DOE PAGES

Reichhardt, Charles; Reichhardt, Cynthia Jane

2015-12-28

In this work, we numerically study the behavior of two-dimensional skyrmions in the presence of a quasi-one-dimensional sinusoidal substrate under the influence of externally applied dc and ac drives. In the overdamped limit, when both dc and ac drives are aligned in the longitudinal direction parallel to the direction of the substrate modulation, the velocity-force curves exhibit classic Shapiro step features when the frequency of the ac drive matches the washboard frequency that is dynamically generated by the motion of the skyrmions over the substrate, similar to previous observations in superconducting vortex systems. In the case of skyrmions, the additionalmore » contribution to the skyrmion motion from a nondissipative Magnus force shifts the location of the locking steps to higher dc drives, and we find that the skyrmions move at an angle with respect to the direction of the dc drive. For a longitudinal dc drive and a perpendicular or transverse ac drive, the overdamped system exhibits no Shapiro steps; however, when a finite Magnus force is present, we find pronounced transverse Shapiro steps along with complex two-dimensional periodic orbits of the skyrmions in the phase-locked regimes. Both the longitudinal and transverse ac drives produce locking steps whose widths oscillate with increasing ac drive amplitude. We examine the role of collective skyrmion interactions and find that additional fractional locking steps occur for both longitudinal and transverse ac drives. Finally, at higher skyrmion densities, the system undergoes a series of dynamical order-disorder transitions, with the skyrmions forming a moving solid on the phase locking steps and a fluctuating dynamical liquid in regimes between the steps.« less

77 FR 63410 - SBIR/STTR Phase I to Phase II Transition Benchmarks

Federal Register 2010, 2011, 2012, 2013, 2014

2012-10-16

.... Small Business Administration. ACTION: Notice of Small Business Innovation Research and Small Business... Administration (SBA) is publishing the Small Business Innovation Research (SBIR) and the Small Business...., Assistant Director, Office of Innovation, Small Business Administration, 409 Third Street SW., Washington...

A Military-Relevant Model of Closed Concussive Head Injury: Longitudinal Studies Characterizing and Validating Single and Repetitive mTBI

DTIC Science & Technology

2014-10-01

Research Program (CCCRP). Provided in this Year 2 Annual Report are the results of our Phase I studies focused on characterizing the neuropathologic...effects of a single concussive impact to repeated concussive impacts using the PCI model. Phase I studies have been completed and these results set...the foundation for Phase II studies designed to evaluate the effects of repeated concussions that occur prior to and after the resolution of the

PLCO Ovarian Phase III Validation Study — EDRN Public Portal

Cancer.gov

Our preliminary data indicate that the performance of CA 125 as a screening test for ovarian cancer can be improved upon by additional biomarkers. With completion of one additional validation step, we will be ready to test the performance of a consensus marker panel in a phase III validation study. Given the original aims of the PLCO trial, we believe that the PLCO represents an ideal longitudinal cohort offering specimens for phase III validation of ovarian cancer biomarkers.

Magnetic Ordering of Erbium and Uranium NICKEL(2) SILICON(2) by Neutron Scattering

NASA Astrophysics Data System (ADS)

Lin, Hong

The magnetic ordering has been studied in UNi _2Si_2 and erbium single crystals by elastic neutron scattering. Abundant results are given regarding the magnetic structure, magnetic phase transitions, and the effect of a magnetic field on these properties. Three ordered phases are observed in UNi _2Si_2. They have been determined to be an incommensurate longitudinal spin density wave with a magnetic wave vector around q = 0.74c ^* in the high temperature phase, a simple body-centred antiferromagnet in the intermediate temperature phase, and a square wave in the low temperature phase. This square wave can be viewed equivalently as a longitudinal spin density wave with q = 2/3c ^* superimposed on a ferromagnetic component. Hysteresis and sample dependence are observed in the low-temperature phase transition. The two lower temperature phase transitions are both first order. The transition to paramagnetism is second order with a critical exponent beta = 0.35 +/- 0.03. When a magnetic field is applied along the c axis, the intermediate temperature phase is destabilised and disappears above a field of 3.5T. Although there is no new phase induced by the field, there exists a reentrant point where the three ordered phases can coexist. Erbium has three distinct ordered phases: the cone phase at low temperatures, the c-axis modulated (CAM) phase at higher temperatures, and the intermediate phase with moments modulated both along c and perpendicular to c. Within these phases the modulation of the moments may lock in to the lattice. The observed weak harmonics of the wave vector q in the basal plane for the cone phase and the q = 1/4c^* structure in the intermediate phase can be explained by a basal-plane spin slip model. The effect of magnetic field along the c axis on the magnetic structure is to stabilise the cone phase and to destabilise the intermediate phase. A new lock-in structure with q = 1/4c^* in the cone phase is induced by fields above 1.8T. The presence of the field also stabilises the lock-in structure with q = 2/7c^* in both the intermediate and the CAM phases.

Main Ionospheric Trough and Equatorial Ionization Anomaly During Substorms With the Different UT Onset Moments

NASA Astrophysics Data System (ADS)

Klimenko, M. V.; Klimenko, V. V.; Bryukhanov, V. V.

2007-05-01

In the given work the numerical calculation results of ionospheric effects of four modeling substorms which have begun in 00, 06, 12 and 18 UT are presented. Calculations are executed on the basis of Global Self-consistent Model of the Thermosphere, Ionosphere and Protonosphere (GSM TIP), developed in WD IZMIRAN, added by the new block of calculation of electric fields in the ionosphere of the Earth for vernal equinox conditions in the minimum of solar activity. In calculations we considered superposition of magnetospheric convection electric field (at set potential differences through polar caps and field aligned currents of the second zone with taking into account of particle precipitation) and dynamo field generated by thermospheric winds without taking into account the tides. It is shown, that in the given statement of problem the substorms cause strong positive disturbances in F-region of ionosphere in night sector. Negative disturbances are much less and arise, mainly, at night in the middle and low latitudes. During substorms longitudinal extent of main ionospheric trough increases. The substorm beginning in 18 UT, causes negative disturbances in high latitudes except for a southern polar cap. Besides there is "stratification" of the main ionospheric trough. As a result in southern hemisphere the additional high-latitude trough which is absent in quiet conditions is formed. "Stratification" of the main ionospheric trough occurs in northern hemisphere at 6 hours after the beginning of the substorm. These "stratifications" are consequence non-stationary magnetospheric convection. Distinction between these events consists that "stratification" in a southern hemisphere occurs in active phase of substorm, and in northern hemisphere in recovery phase. During a substorm beginning in 00 UT, foF2 increases in all northern polar cap. Positive disturbances of foF2 in the equatorial anomaly region cause all presented substorms, except for a substorm beginning in 18 UT. This substorm causes small negative disturbances in the equatorial anomaly region in the Indian longitudinal sector.

Associations of Child and Adolescent Mastery Motivation and Self-Regulation With Adult Outcomes: A Longitudinal Study of Individuals With Down Syndrome.

PubMed

Gilmore, Linda; Cuskelly, Monica

2017-05-01

This 20-year prospective longitudinal study focuses on the contribution of mastery motivation and self-regulation to adult outcomes for individuals with Down syndrome. In earlier phases of the research, 25 participants completed measures of cognitive ability, mastery motivation and self-regulation in childhood (4 to 6 years) and adolescence (11 to 15 years). In the adult phase reported here, self-determination and adaptive behavior were assessed in 21 of the original participants at age 23 to 26 years. Mastery motivation and self-regulation made unique contributions to adult outcomes, over and above the effects of cognitive ability. The findings provide powerful evidence about the important role of child and adolescent mastery motivation and self-regulation for the adult lives of individuals with Down syndrome.

BEAM OPTIMIZATION STUDY FOR AN X-RAY FEL OSCILLATOR AT THE LCLS-II

DOE Office of Scientific and Technical Information (OSTI.GOV)

Qin, Weilun; Huang, S.; Liu, K.X.

2016-06-01

The 4 GeV LCLS-II superconducting linac with high repetition beam rate enables the possibility to drive an X-Ray FEL oscillator at harmonic frequencies *. Compared to the regular LCLS-II machine setup, the oscillator mode requires a much longer bunch length with a relatively lower current. Also a flat longitudinal phase space distribution is critical to maintain the FEL gain since the X-ray cavity has extremely narrow bandwidth. In this paper, we study the longitudinal phase space optimization including shaping the initial beam from the injector and optimizing the bunch compressor and dechirper parameters. We obtain a bunch with a flatmore » energy chirp over 400 fs in the core part with current above 100 A. The optimization was based on LiTrack and Elegant simulations using LCLS-II beam parameters.« less

Experimental Demonstration of Longitudinal Beam Phase-Space Linearizer in a Free-Electron Laser Facility by Corrugated Structures

NASA Astrophysics Data System (ADS)

Deng, Haixiao; Zhang, Meng; Feng, Chao; Zhang, Tong; Wang, Xingtao; Lan, Taihe; Feng, Lie; Zhang, Wenyan; Liu, Xiaoqing; Yao, Haifeng; Shen, Lei; Li, Bin; Zhang, Junqiang; Li, Xuan; Fang, Wencheng; Wang, Dan; Couprie, Marie-emmanuelle; Lin, Guoqiang; Liu, Bo; Gu, Qiang; Wang, Dong; Zhao, Zhentang

2014-12-01

Removal of the undesired time-energy correlations in the electron beam is of paramount importance for efficient lasing of a high-gain free-electron laser. Recently, it has been theoretically and experimentally demonstrated that the longitudinal wakefield excited by the electrons themselves in a corrugated structure allows for precise control of the electron beam phase space. In this Letter, we report the first utilization of a corrugated structure as a beam linearizer in the operation of a seeded free-electron laser driven by a 140 MeV linear accelerator, where a gain of ˜10 000 over spontaneous emission was achieved at the second harmonic of the 1047 nm seed laser, and a free-electron laser bandwidth narrowing by 50% was observed, in good agreement with the theoretical expectations.

Differentiating the growth phases of single bacteria using Raman spectroscopy

NASA Astrophysics Data System (ADS)

Strola, S. A.; Marcoux, P. R.; Schultz, E.; Perenon, R.; Simon, A.-C.; Espagnon, I.; Allier, C. P.; Dinten, J.-M.

2014-03-01

In this paper we present a longitudinal study of bacteria metabolism performed with a novel Raman spectrometer system. Longitudinal study is possible with our Raman setup since the overall procedure to localize a single bacterium and collect a Raman spectrum lasts only 1 minute. Localization and detection of single bacteria are performed by means of lensfree imaging, whereas Raman signal (from 600 to 3200 cm-1) is collected into a prototype spectrometer that allows high light throughput (HTVS technology, Tornado Spectral System). Accomplishing time-lapse Raman spectrometry during growth of bacteria, we observed variation in the net intensities for some band groups, e.g. amides and proteins. The obtained results on two different bacteria species, i.e. Escherichia coli and Bacillus subtilis clearly indicate that growth affects the Raman chemical signature. We performed a first analysis to check spectral differences and similarities. It allows distinguishing between lag, exponential and stationary growth phases. And the assignment of interest bands to vibration modes of covalent bonds enables the monitoring of metabolic changes in bacteria caused by growth and aging. Following the spectra analysis, a SVM (support vector machine) classification of the different growth phases is presented. In sum this longitudinal study by means of a compact and low-cost Raman setup is a proof of principle for routine analysis of bacteria, in a real-time and non-destructive way. Real-time Raman studies on metabolism and viability of bacteria pave the way for future antibiotic susceptibility testing.

Fusion splicing small-core photonic crystal fibers and single-mode fibers by repeated arc discharges.

PubMed

Xiao, Limin; Jin, Wei; Demokan, M S

2007-01-15

We demonstrate a novel method for low-loss splicing small-core photonic crystal fibers (PCFs) and single-mode fibers (SMFs) by repeated arc discharges using a conventional fusion splicer. An optimum mode field match at the interface of PCF-SMF and an adiabatic mode field variation in the longitudinal direction of the small-core PCF can be achieved by repeated arc discharges applied over the splicing joint to gradually collapse the air holes of the small-core PCF. This method is simple and offers a practical solution for light coupling between small-core PCFs and SMFs.

Fusion splicing small-core photonic crystal fibers and single-mode fibers by repeated arc discharges

NASA Astrophysics Data System (ADS)

Xiao, Limin; Jin, Wei; Demokan, M. S.

2007-01-01

We demonstrate a novel method for low-loss splicing small-core photonic crystal fibers (PCFs) and single-mode fibers (SMFs) by repeated arc discharges using a conventional fusion splicer. An optimum mode field match at the interface of PCF-SMF and an adiabatic mode field variation in the longitudinal direction of the small-core PCF can be achieved by repeated arc discharges applied over the splicing joint to gradually collapse the air holes of the small-core PCF. This method is simple and offers a practical solution for light coupling between small-core PCFs and SMFs.

Wave propagation in fluid-conveying viscoelastic carbon nanotubes under longitudinal magnetic field with thermal and surface effect via nonlocal strain gradient theory

NASA Astrophysics Data System (ADS)

Zhen, Yaxin; Zhou, Lin

2017-03-01

Based on nonlocal strain gradient theory, wave propagation in fluid-conveying viscoelastic single-walled carbon nanotubes (SWCNTs) is studied in this paper. With consideration of thermal effect and surface effect, wave equation is derived for fluid-conveying viscoelastic SWCNTs under longitudinal magnetic field utilizing Euler-Bernoulli beam theory. The closed-form expressions are derived for the frequency and phase velocity of the wave motion. The influences of fluid flow velocity, structural damping coefficient, temperature change, magnetic flux and surface effect are discussed in detail. SWCNTs’ viscoelasticity reduces the wave frequency of the system and the influence gets remarkable with the increase of wave number. The fluid in SWCNTs decreases the frequency of wave propagation to a certain extent. The frequency (phase velocity) gets larger due to the existence of surface effect, especially when the diameters of SWCNTs and the wave number decrease. The wave frequency increases with the increase of the longitudinal magnetic field, while decreases with the increase of the temperature change. The results may be helpful for better understanding the potential applications of SWCNTs in nanotechnology.

Analysis of radial and longitudinal field of plasma wakefield generated by a Laguerre-Gauss laser pulse

DOE Office of Scientific and Technical Information (OSTI.GOV)

Firouzjaei, Ali Shekari; Shokri, Babak

In the present paper, we study the wakes known as the donut wake which is generated by Laguerre-Gauss (LG) laser pulses. Effects of the special spatial profile of a LG pulse on the radial and longitudinal wakefields are presented via an analytical model in a weakly non-linear regime in two dimensions. Different aspects of the donut-shaped wakefields have been analyzed and compared with Gaussian-driven wakes. There is also some discussion about the accelerating-focusing phase of the donut wake. Variations of longitudinal and radial wakes with laser amplitude, pulse length, and pulse spot size have been presented and discussed. Finally, wemore » present the optimum pulse duration for such wakes.« less

Quantum tachyons

NASA Astrophysics Data System (ADS)

Tomaschitz, R.

2005-02-01

The interaction of superluminal radiation with matter in atomic bound-bound and bound-free transitions is investigated. We study transitions in the relativistic hydrogen atom effected by superluminal quanta. The superluminal radiation field is coupled by minimal substitution to the Dirac equation in a Coulomb potential. We quantize the interaction to obtain the transition matrix for induced and spontaneous superluminal radiation in hydrogen-like ions. The tachyonic photoelectric effect is scrutinized, the cross-sections for ground state ionization by transversal and longitudinal tachyons are derived. We examine the relativistic regime, high electronic ejection energies, as well as the first order correction to the non-relativistic cross-sections. In the ultra-relativistic limit, both the longitudinal and transversal cross-sections are peaked at small but noticeably different scattering angles. In the non-relativistic limit, the longitudinal cross-section has two maxima, and its minimum is located at the transversal maximum. Ionization cross-sections can thus be used to discriminate longitudinal radiation from transversal tachyons and photons.

Dynamic Bayesian network modeling for longitudinal brain morphometry

PubMed Central

Chen, Rong; Resnick, Susan M; Davatzikos, Christos; Herskovits, Edward H

2011-01-01

Identifying interactions among brain regions from structural magnetic-resonance images presents one of the major challenges in computational neuroanatomy. We propose a Bayesian data-mining approach to the detection of longitudinal morphological changes in the human brain. Our method uses a dynamic Bayesian network to represent evolving inter-regional dependencies. The major advantage of dynamic Bayesian network modeling is that it can represent complicated interactions among temporal processes. We validated our approach by analyzing a simulated atrophy study, and found that this approach requires only a small number of samples to detect the ground-truth temporal model. We further applied dynamic Bayesian network modeling to a longitudinal study of normal aging and mild cognitive impairment — the Baltimore Longitudinal Study of Aging. We found that interactions among regional volume-change rates for the mild cognitive impairment group are different from those for the normal-aging group. PMID:21963916

Longitudinal structure function from logarithmic slopes of F2 at low x

NASA Astrophysics Data System (ADS)

Boroun, G. R.

2018-01-01

Using Laplace transform techniques, I calculate the longitudinal structure function FL(x ,Q2) from the scaling violations of the proton structure function F2(x ,Q2) and make a critical study of this relationship between the structure functions at leading order (LO) up to next-to-next-to leading order (NNLO) analysis at small x . Furthermore, I consider heavy quark contributions to the relation between the structure functions, which leads to compact formula for Nf=3 +Heavy . The nonlinear corrections to the longitudinal structure function at LO up to NNLO analysis are shown in the Nf=4 (light quark flavor) based on the nonlinear corrections at R =2 and R =4 GeV-1 . The results are compared with experimental data of the longitudinal proton structure function FL in the range of 6.5 ≤Q2≤800 GeV2 .

Critical Current Properties in Longitudinal Magnetic Field of YBCO Superconductor with APC

NASA Astrophysics Data System (ADS)

Kido, R.; Kiuchi, M.; Otabe, E. S.; Matsushita, T.; Jha, A. K.; Matsumoto, K.

The critical current density (Jc) properties of the Artificial Pinning Center (APC) introduced YBa2Cu3O7 (YBCO) films in the longitudinal magnetic field were measured. Y2O3 or Y2BaCuO5 (Y211) was introduced as APCs to YBCO, and YBCO films with APC were fabricated on SrTiO3 single crystal substrate. The sizes of Y2O3 and Y211 were 5-10 nm and 10-20 nm, respectively. As a result, Jc enhancement in the longitudinal magnetic field was observed in Y2O3 introduced YBCO films. However, it was not observed in Y211 introduced YBCO films. Therefore, it was considered that Jc properties in the longitudinal magnetic field were affected by introducing of small size APC, and it was necessary that APC does not disturb the current pathway in the superconductor.

Coherent X-ray diffraction imaging of zinc oxide crystals

NASA Astrophysics Data System (ADS)

Leake, S. J.

Zinc Oxide (ZnO) exhibits a plethora of physical properties potentially advantageous in many roles and is why it one of the most studied semiconductor compounds. When doped or in its intrinsic state ZnO demonstrates a multitude of electronic, optical and magnetic properties in a large variety of manufacturable morphologies. Thus it is inherently important to understand why these properties arise and the impact potentially invasive sample preparation methods have for both the function and durability of the material and its devices. Coherent X-ray Diffraction Imaging (CXDI) is a recently established non-destructive technique which can probe the whole three dimensional structure of small crystalline materials and has the potential for sub angstrom strain resolution. The iterative methods employed to overcome the `phase problem' are described fully. CXDI studies of wurtzite ZnO crystals in the rod morphology with high aspect ratio are presented. ZnO rods synthesised via Chemical Vapour Transport Deposition were studied in post growth state and during in-situ modification via metal evaporation processing and annealing. Small variations in post growth state were observed, the physical origin of which remains unidentified. The doping of a ZnO crystal with Iron, Nickel and Cobalt by thermal evaporation and subsequent annealing was studied. The evolution of diffusing ions into the crystal lattice from was not observed, decomposition was found to be the dominant process. Improvements in experimental technique allowed multiple Bragg reflections from a single ZnO crystal to be measured for the first time. Large aspect ratio ZnO rods were used to probe the coherence properties of the incident beam. The longitudinal coherence function of the illuminating radiation was mapped using the visibility of the interference pattern at each bragg reflection and an accurate estimate of the longitudinal coherence length obtained, xi(L) = 0.66pm 0.02 mu m. The consequences for data analysis are discussed. The combination of multiple Bragg reflections to realise three dimensional displacement fields was also approached.

The Effects of Magnetic-Field Geometry on Longitudinal Oscillations of Solar Prominences: Cross-Sectional Area Variation for Thin Tubes

NASA Technical Reports Server (NTRS)

Luna, M.; Diaz, A. J.; Oliver, R.; Terradas, J.; Karpen, J.

2016-01-01

Solar prominences are subject to both field-aligned (longitudinal) and transverse oscillatory motions, as evidenced by an increasing number of observations. Large-amplitude longitudinal motions provide valuable information on the geometry of the filament channel magnetic structure that supports the cool prominence plasma against gravity. Our pendulum model, in which the restoring force is the gravity projected along the dipped field lines of the magnetic structure, best explains these oscillations. However, several factors can influence the longitudinal oscillations, potentially invalidating the pendulum model. Aims. The aim of this work is to study the influence of large-scale variations in the magnetic field strength along the field lines, i.e., variations of the cross-sectional area along the flux tubes supporting prominence threads. Methods. We studied the normal modes of several flux tube configurations, using linear perturbation analysis, to assess the influence of different geometrical parameters on the oscillation properties. Results. We found that the influence of the symmetric and asymmetric expansion factors on longitudinal oscillations is small.Conclusions. We conclude that the longitudinal oscillations are not significantly influenced by variations of the cross-section of the flux tubes, validating the pendulum model in this context.

Burrowing by small polychaetes - mechanics, behavior and muscle structure of Capitella sp.

PubMed

Grill, Susann; Dorgan, Kelly M

2015-05-15

Worms of different sizes extend burrows through muddy sediments by fracture, applying dorso-ventral forces that are amplified at the crack tip. Smaller worms displace sediments less than larger worms and therefore are limited in how much force they can apply to burrow walls. We hypothesized that small worms would exhibit a transition in burrowing mechanics, specifically a lower limit in body size for the ability to burrow by fracture, corresponding with an ontogenetic transition in muscle morphology. Kinematics of burrowing in a mud analog, external morphology and muscle arrangement were examined in juveniles and adults of the small polychaete Capitella sp. We found that it moves by peristalsis, and no obvious differences were observed among worms of different sizes; even very small juveniles were able to burrow through a clear mud analog by fracture. Interestingly, we found that in addition to longitudinal and circular muscles needed for peristaltic movements, left- and right-handed helical muscles wrap around the thorax of worms of all sizes. We suggest that in small worms helical muscles may function to supplement forces generated by longitudinal muscles and to maintain hydrostatic pressure, enabling higher forces to be exerted on the crack wall. Further research is needed, however, to determine whether surficial sediments inhabited by small worms fail by fracture or plastically deform under forces of the magnitudes applied by Capitella sp. © 2015. Published by The Company of Biologists Ltd.

The impact of the 17 March 2015- St. Patrick's Day storm on the evolutionary pattern of Equatorial Ionization Anomaly over the Indian longitudes using high resolution spatio-temporal TEC maps - New insights

NASA Astrophysics Data System (ADS)

Yadav, S.; Sunda, S.; Sridharan, R.

2016-12-01

The impact of the St. Patrick's Day storm (17 March 2015) on the major equatorial electro-dynamical process viz., the Equatorial Ionization Anomaly (EIA) has been assessed using 2D (lat. x long.) total electron content (TEC) maps generated from the ground based SBAS (Satellite Based Augmentation System) enabled receiver data. The various aspects of EIA viz., i) evolution/devolution, ii) longitudinal structure, and iii) its variability during different phases of a geomagnetic storm have been brought out. These 2D TEC maps, which have a large latitudinal (5̊ S-45° N) and longitudinal (55-110° E) coverage, show the complete reversal in the longitudinal structure of EIA during the recovery phase of the storm as compared to the quiet day. These results have been explained in the light of the combined effects of the storm associated processes viz., i) the penetration electric fields of magnetosphere origin, ii) storm induced thermospheric winds, and iii) activation of the consequent disturbance dynamo, effectively distorting the longitudinal wave number 4 (WN4) structure of the EIA. It has been shown unambiguously that even a separation of few degrees in longitude ( 30̊) could experience significantly different forcings. The relevance and the far reaching consequences of the study in the light of the current trends and requirements for reliable satellite based navigation are highlighted.

Creativity and Occupational Accomplishments Among Intellectually Precocious Youths: An Age 13 to Age 33 Longitudinal Study

ERIC Educational Resources Information Center

Wai, Jonathan; Lubinski, David; Benbow, Camilla P.

2005-01-01

This study tracks intellectually precocious youths (top 1%) over 20 years. Phase 1 (N = 1,243 boys, 732 girls) examines the significance of age 13 ability differences within the top 1% for predicting doctorates, income, patents, and tenure at U.S. universities ranked within the top 50. Phase 2 (N = 323 men, 188 women) evaluates the robustness of…

Reduce, Reuse, Recycle: The Longitudinal Value of Local Cut Scores Using State Test Data

ERIC Educational Resources Information Center

Nelson, Peter M.; Van Norman, Ethan R.; VanDerHeyden, Amanda

2017-01-01

We used existing reading (n = 1,498) and math (n = 2,260) data to evaluate state test scores for screening middle school students. In Phase 1, state test data were used to create a research-derived cut score that was optimal for predicting state test performance the following year. In Phase 2, those cut scores were applied with future cohorts.…

Annual and interannual variations of phytoplankton pigment concentration and upwelling along the Pacific equator

NASA Technical Reports Server (NTRS)

Halpern, David; Feldman, Gene C.

1994-01-01

The following variables along the Pacific equator from 145 deg E to 95 deg W were employed: surface layer phytoplankton pigment concentrations derived from Nimbus 7 coastal zone color scanner (CZCS) measurements of ocean color radiances; vertical velocities simulated at the 90-m bottom of the euphotic layer from a wind-driven ocean general circulation model; and nitrate concentrations estimated from model-simulated temperature. The upward flux of nitrate into the euphotic layer was calculated from the simulated vertical motion and nitrate concentration. The CZCS-derived phytoplankton pigment concentration was uniform from 175 deg to 95 deg W. Longitudinal profiles of upwelling, phytoplankton biomass, and 90-m nitrate flux were of different shapes. The small annual cycles of the phytoplankton pigment and nitrate flux were in phase: increased phytoplankton biomass was associated with increased upward nitrate flux, but the phase was not consistent with the annual cycles of the easterly wind or of the upwelling intensity. Variation of phytoplankton pigment concentration was greater during El Nino than during the annual cycle. The substantially reduced phytoplankton pigment concentration observed during El Nino was associated with smaller upward nitrate flux. Phytoplankton biomass during non-El Nino conditions was not related to nitrate flux into the euphotic layer.

Structural change and charge ordering correlated ultrasonic anomalies in La1-xCaxMnO3 (x=0.5,0.83) perovskite

NASA Astrophysics Data System (ADS)

Zheng, R. K.; Zhu, C. F.; Xie, J. Q.; Li, X. G.

2001-01-01

Ultrasonic sound velocity and attenuation have been measured in polycrystalline manganese oxide La1-xCaxMnO3 (x=0.5,0.83,1.0) at a frequency of 10 MHz. For x=0.5, on cooling down from high temperature, a slight softening of the sound velocity above the charge ordering transition temperature TCO and dramatic stiffening below TCO coincided with big attenuation peaks for both longitudinal and transverse waves were observed. It was found that these ultrasonic anomalies near TCO are correlated with the fine structure (i.e., the lattice parameters) change caused by the Jahn-Teller effect. For x=0.83, the sound velocity starts to soften dramatically with decreasing temperature from higher temperature to TS (180 K), and stiffens dramatically below TS. The large softening and stiffening of the sound velocity accompanied by a big attenuation peak are strongly correlated with a cubic-to-tetragonal structural phase transition at TS, which is confirmed by the low-temperature powder x-ray diffraction measurements. It is suggested that this structural phase transition be due to the Jahn-Teller distortion of the Mn3+O6 octahedra and related to the charge ordering transition. For CaMnO3, the anomaly in sound velocity is small.

Characterisation of melt spun Ni-Ti shape memory Ribbons' microstructure

NASA Astrophysics Data System (ADS)

Mehrabi, Kambiz; Brunčko, Mihael; Kneissl, Albert C.; Čolič, Miodrag; Stamenković, Dragoslav; Ferčec, Janko; Anžel, Ivan; Rudolf, Rebeka

2012-06-01

NiTi alloys are the most technologically important medical Shape Memory Alloys in a wide range of applications used in Orthopaedics, Neurology, Cardiology and interventional Radiology as guide-wires, self-expandable stents, stent grafts, inferior vena cava filters and clinical instruments. This paper discusses the use of rapid solidification by the melt spinning method for the preparation of thin NiTi ribbons for medical uses. Generally, the application of rapid solidification via melt-spinning can change the microstructure drastically, which improves ductility and shape memory characteristics and leads to samples with small dimensions. As the increase in the wheel speed led to a reduced ribbon thickness, the cooling rate increased and, therefore, the martensitic substructure became finer. Furthermore, no transition from the crystalline phase to the amorphous phase was obtained by increasing the cooling rate, even at a wheel speed of 30 m/s. Specimens for our metallographic investigation were cut from the longitudinal cross sections of melt-spun ribbons. Conventional TEM studies were carried out with an acceleration voltage of 120 kV. Additionally, the chemical composition of the samples was examined with a TEM equipped with an EDX analyser. The crystallographic structure was determined using Bragg-Brentano x-ray diffraction with Cu-Kα radiation at room temperature.

Eigenvalue Problems.

DTIC Science & Technology

1987-06-01

Vibration of an Elastic Bar We are interested in studying the small, longitudinal vibra- tions of a longitudinally loaded, elastically supported, elastic...u 2 + + 2u O(( m,Q Uk .(J- MO In the study of eigenvalue problems, central use will be made of Rellich’s theorem (cf. Agmon [19651), which states...H , where a > 0. Sufficient conditions for (4.2) - (4.4) to hold were given in Section 3; cf. (3.15) -(3.17). For the study of (4.1) it is useful to

High longitudinal relaxivity of ultra-small gadolinium oxide prepared by microsecond laser ablation in diethylene glycol

NASA Astrophysics Data System (ADS)

Luo, Ningqi; Tian, Xiumei; Xiao, Jun; Hu, Wenyong; Yang, Chuan; Li, Li; Chen, Dihu

2013-04-01

Ultra-small gadolinium oxide (Gd2O3) can be used as T1-weighted Magnetic Resonance Imaging (MRI) contrast agent own to its high longitudinal relaxivity (r1) and has attracted intensive attention in these years. In this paper, ultra-small Gd2O3 nanoparticles of 3.8 nm in diameter have been successfully synthesized by a microsecond laser ablating a gadolinium (Gd) target in diethylene glycol (DEG). The growth inhibition effect induced by the large viscosity of DEG makes it possible to synthesize ultra-small Gd2O3 by laser ablation in DEG. The r1 value and T1-weighted MR images are measured by a 3.0 T MRI spectroscope. The results show these nanoparticles with a high r1 value of 9.76 s-1 mM-1 to be good MRI contrast agents. We propose an explanation for the high r1 value of ultra-small Gd2O3 by considering the decreasing factor (surface to volume ratio of the nanoparticles, S/V) and the increasing factor (water hydration number of the Gd3+ on Gd2O3 surface, q), which offer a new look into the relaxivity studies of MRI contrast agents. Our research provides a new approach to preparing ultra-small Gd2O3 of high r1 value by laser ablation in DEG and develops the understanding of high relaxivity of ultra-small Gd2O3 MRI contrast agents.

NASA SBIR product catalog, 1990

NASA Technical Reports Server (NTRS)

Schwenk, F. Carl; Gilman, J. A.

1990-01-01

Since 1983 the NASA Small Business Innovation Research (SBIR) program has benefitted both the agency and the high technology small business community. By making it possible for more small businesses to participate in NASA's research and development, SBIR also provides opportunities for these entrepreneurs to develop products which may also have significant commercial markets. Structured in three phases, the SBIR program uses Phase 1 to assess the technical feasibility of novel ideas proposed by small companies and Phase 2 to conduct research and development on the best concepts. Phase 3, not funded by SBIR, is the utilization and/or commercialization phase. A partial list of products of NASA SBIR projects which have advanced to some degree into Phase 3 are provided with a brief description.

Longitudinal mode selection in a delay-line homogeneously broadened oscillator with a fast saturable amplifier.

PubMed

Fleyer, Michael; Horowitz, Moshe

2017-05-01

Homogeneously broadened delay-line oscillators such as lasers or optoelectronic oscillators (OEOs) can potentially oscillate in a large number of cavity modes that are supported by their amplifier bandwidth. In a continuous wave operating mode, the oscillating mode is selected between one or few cavity modes that experience the highest small-signal gain. In this manuscript, we show that the oscillation mode of a homogeneously broadened oscillator can be selected from a large number of modes in a frequency region that can be broader than the full width at half maximum of the effective cavity filter. The mode is selected by a short-time injection of an external signal into the oscillator. After the external signal is turned off, the oscillation is maintained in the selected mode even if this mode has a significantly lower small-signal gain than that of other cavity modes. The stability of the oscillation is obtained due to nonlinear saturation effect in the oscillator amplifier. We demonstrate, experimentally and theoretically, mode selection in a long cavity OEO. We could select any desired mode between 400 cavity modes while maintaining ultra-low phase noise in the selected mode and in the non-oscillating modes. No mode-hopping was observed during our maximum measurement duration of about 24 hours.

Intrinsic Work Value-Reward Dissonance and Work Satisfaction during Young Adulthood

PubMed Central

Porfeli, Erik J.; Mortimer, Jeylan T.

2010-01-01

Previous research suggests that discrepancies between work values and rewards are indicators of dissonance that induce change in both to reduce such dissonance over time. The present study elaborates this model to suggest parallels with the first phase of the extension- and-strain curve. Small discrepancies or small increases in extension are presumed to be almost unnoticeable, while increasingly large discrepancies are thought to yield exponentially increasing strain. Work satisfaction is a principal outcome of dissonance; hence, work value-reward discrepancies are predicted to diminish work satisfaction in an exponential fashion. Findings from the work and family literature, however, lead to the prediction that this curvilinear association will be moderated by gender and family roles. Using longitudinal data spanning the third decade of life, the results suggest that intrinsic work value-reward discrepancies, as predicted, are increasingly associated, in a negative curvilinear fashion, with work satisfaction. This pattern, however, differs as a function of gender and family roles. Females who established family roles exhibited the expected pattern while other gender by family status groups did not. The results suggest that gender and family roles moderate the association between intrinsic work value-reward dissonance and satisfaction. In addition, women who remained unmarried and childless exhibited the strongest associations between occupational rewards and satisfaction. PMID:20526434

Intrinsic Work Value-Reward Dissonance and Work Satisfaction during Young Adulthood.

PubMed

Porfeli, Erik J; Mortimer, Jeylan T

2010-06-01

Previous research suggests that discrepancies between work values and rewards are indicators of dissonance that induce change in both to reduce such dissonance over time. The present study elaborates this model to suggest parallels with the first phase of the extension- and-strain curve. Small discrepancies or small increases in extension are presumed to be almost unnoticeable, while increasingly large discrepancies are thought to yield exponentially increasing strain. Work satisfaction is a principal outcome of dissonance; hence, work value-reward discrepancies are predicted to diminish work satisfaction in an exponential fashion. Findings from the work and family literature, however, lead to the prediction that this curvilinear association will be moderated by gender and family roles. Using longitudinal data spanning the third decade of life, the results suggest that intrinsic work value-reward discrepancies, as predicted, are increasingly associated, in a negative curvilinear fashion, with work satisfaction. This pattern, however, differs as a function of gender and family roles. Females who established family roles exhibited the expected pattern while other gender by family status groups did not. The results suggest that gender and family roles moderate the association between intrinsic work value-reward dissonance and satisfaction. In addition, women who remained unmarried and childless exhibited the strongest associations between occupational rewards and satisfaction.

Magnetoelectric coupling and electrical properties of inorganic-organic based LSMO - PVDF hybrid nanocomposites

NASA Astrophysics Data System (ADS)

Debnath, Rajesh; Mandal, S. K.; Dey, P.; Nath, A.

2018-04-01

We have investigated strain mediated magnetoelectric coupling and ac electrical properties of 0.5La0.7Sr0.3MnO3-0.5 Polyvinylidene Fluoride nanocomposites at room temperature. The sample has been prepared through low temperature pyrophoric chemical process. The detailed study of X-ray diffraction pattern shows simultaneous co-existence of two phases of nanometric grains. Field emission scanning electron micrograph shows the absence of any phase segregation and good chemical homogeneity in composites. The magnetoelectric voltage is measured in both longitudinal and transverse direction at a frequency of 73 Hz. The magnetoelectric coefficient in transverse direction is found to ˜0.17 mV/cmOe and in longitudinal direction it is found to ˜0.08 mV/cmOe. With the application of dc magnetic field the real and imaginary part of impedance are increased where the dielectric constant has been decreased. Nyquist plots have been fitted using two parallel combinations of resistances - constant phase element circuits considering dominant role of grains and grain boundaries resistance in the conduction process of the sample.

End-to-end simulation of bunch merging for a muon collider

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bao, Yu; Stratakis, Diktys; Hanson, Gail G.

2015-05-03

Muon accelerator beams are commonly produced indirectly through pion decay by interaction of a charged particle beam with a target. Efficient muon capture requires the muons to be first phase-rotated by rf cavities into a train of 21 bunches with much reduced energy spread. Since luminosity is proportional to the square of the number of muons per bunch, it is crucial for a Muon Collider to use relatively few bunches with many muons per bunch. In this paper we will describe a bunch merging scheme that should achieve this goal. We present for the first time a complete end-to-end simulationmore » of a 6D bunch merger for a Muon Collider. The 21 bunches arising from the phase-rotator, after some initial cooling, are merged in longitudinal phase space into seven bunches, which then go through seven paths with different lengths and reach the final collecting "funnel" at the same time. The final single bunch has a transverse and a longitudinal emittance that matches well with the subsequent 6D rectilinear cooling scheme.« less

The Coherent Backscattering Opposition Effect: Measurements at Very Small Phase Angles

NASA Technical Reports Server (NTRS)

Nelson, R.; Hapke, B.; Smythe, W.; Horn, L.; Herrera, P.; Gharakanian, V.

1993-01-01

This oral presentation explains that measurements of the opposition surge (the nonlinear increase in reflectance seen in particulate materials when observed at small phase angles) are the first ever made using the JPL long-arm goniometer, which permits very small phase angle measuremnets to be made.

Defense Small Business Innovation Research Program (SBIR). Abstracts of Phase 2 Awards, 1984.

DTIC Science & Technology

165 proposals for funding in Phase II of the Small Business Innovation Research (SBIR) Program. These proposals were selected from those submitted by... small research and development firms awarded Phase I contracts from the FY 1984 solicitation. In order to make information available on the technical

New insights into Mesozoic cycad evolution: an exploration of anatomically preserved Cycadaceae seeds from the Jurassic Oxford Clay biota

PubMed Central

Rees, Andrew R.; Raine, Robert J.; Rothwell, Gar W.; Hollingworth, Neville T.J.

2017-01-01

Most knowledge concerning Mesozoic Era floras has come from compression fossils. This has been augmented in the last 20 years by rarer permineralized material showing cellular preservation. Here, we describe a new genus of anatomically preserved gymnosperm seed from the Callovian–Oxfordian (Jurassic) Oxford Clay Formation (UK), using a combination of traditional sectioning and synchrotron radiation X-ray micro-tomography (SRXMT). Oxfordiana motturii gen. et sp. nov. is large and bilaterally symmetrical. It has prominent external ribs, and has a three-layered integument comprising: a narrow outer layer of thick walled cells; a thick middle parenchymatous layer; and innermost a thin fleshy layer. The integument has a longitudinal interior groove and micropyle, enveloping a nucellus with a small pollen chamber. The large size, bilateral symmetry and integumentary groove demonstrate an affinity for the new species within the cycads. Moreover, the internal groove in extant taxa is an autapomorphy of the genus Cycas, where it facilitates seed germination. Based upon the unique seed germination mechanism shared with living species of the Cycadaceae, we conclude that O. motturii is a member of the stem-group lineage leading to Cycas after the Jurassic divergence of the Cycadaceae from other extant cycads. SRXMT—for the first time successfully applied to fossils already prepared as slides—reveals the distribution of different mineral phases within the fossil, and allows us to evaluate the taphonomy of Oxfordiana. An early pyrite phase replicates the external surfaces of individual cells, a later carbonate component infilling void spaces. The resulting taphonomic model suggests that the relatively small size of the fossils was key to their exceptional preservation, concentrating sulfate-reducing bacteria in a locally closed microenvironment and thus facilitating soft-tissue permineralization. PMID:28875075

Turbulent Boundary Layers in Oscillating Flows. Part 1: an Experimental and Computational Study

NASA Technical Reports Server (NTRS)

Cook, W. J.

1986-01-01

An experimental-computational study of the behavior of turbulent boundary layers for oscillating air flows over a plane surface with a small favorable mean pressure gradient is described. Experimental studies were conducted for boundary layers generated on the test section wall of a facility that produces a flow with a mean free stream velocity and a superposed nearly-pure sinusoidal component over a wide range of frequency. Flow at a nominal mean free stream velocity of 50 m/s were studied at atmospheric pressure and temperature at selected axial positions over a 2 m test length for frequencies ranging from 4 to 29 Hz. Quantitative experimental results are presented for unsteady velocity profiles and longitudinal turbulence levels obtained from hot wire anemometer measurements at three axial positions. Mean velocity profiles for oscillating flows were found to exhibit only small deviations from corresponding steady flow profiles, while amplitudes and phase relationships exhibited a strong dependence on axial position and frequency. Since sinusoidal flows could be generated over a wide range of frequency, studies at fixed values of reduced frequency at different axial positions were studied. Results show that there is some utility in the use of reduced frequency to correlate unsteady velocity results. The turbulence level u' sub rms was observed to vary essentially sinusoidally around values close to those measured in steady flow. However, the amplitude of oscillation and phase relations for turbulence level were found to be strongly frequency dependent. Numerical predictions were obtained using an unsteady boundary layer computational code and the Cebeci-Smith and Glushko turbulence models. Predicted quantities related to unsteady velocity profiles exhibit fair agreement with experiment when the Cebeci-Smith turbulence model is used.

Longitudinal Modeling of Functional Decline Associated with Pathologic Alzheimer's Disease in Older Persons without Cognitive Impairment.

PubMed

Wang, Dai; Schultz, Tim; Novak, Gerald P; Baker, Susan; Bennett, David A; Narayan, Vaibhav A

2018-01-01

Therapeutic research on Alzheimer's disease (AD) has moved to intercepting the disease at the preclinical phase. Most drugs in late development have focused on the amyloid hypothesis. To understand the magnitude of amyloid-related functional decline and to identify the functional domains sensitive to decline in a preclinical AD population. Data were from the Religious Orders Study and the Rush Memory and Aging Project. Cognitive decline was measured by a modified version of the Alzheimer's Disease Cooperative Study Preclinical Alzheimer Cognitive Composite. The trajectories of functional decline, as measured by the instrumental and basic activities of daily living, were longitudinally modeled in 484 participants without cognitive impairment at baseline and having both a final clinical and a postmortem neuropathology assessment of AD. Individuals with different final clinical diagnoses had different trajectories of cognitive and functional decline. Individuals with AD dementia, minor cognitive impairment, and no cognitive impairment had the most, intermediate, and least declines. While individuals with pathologic AD had significantly more cognitive decline over time than those without, the magnitude of difference in functional decline between these two groups was small. Functional domains such as handling finance and handling medications were more sensitive to decline. Demonstrating the functional benefit of an amyloid-targeting drug represents a significant challenge as elderly people experience functional decline due to a wide range of reasons with limited manifestation attributable to AD neuropathology. More sensitive functional scales focusing on the functional domains sensitive to decline in preclinical AD are needed.

Microscopic origin of black hole reentrant phase transitions

NASA Astrophysics Data System (ADS)

Zangeneh, M. Kord; Dehyadegari, A.; Sheykhi, A.; Mann, R. B.

2018-04-01

Understanding the microscopic behavior of the black hole ingredients has been one of the important challenges in black hole physics during the past decades. In order to shed some light on the microscopic structure of black holes, in this paper, we explore a recently observed phenomenon for black holes namely reentrant phase transition, by employing the Ruppeiner geometry. Interestingly enough, we observe two properties for the phase behavior of small black holes that leads to reentrant phase transition. They are correlated and they are of the interaction type. For the range of pressure in which the system underlies reentrant phase transition, it transits from the large black holes phase to the small one which possesses higher correlation than the other ranges of pressures. On the other hand, the type of interaction between small black holes near the large/small transition line differs for usual and reentrant phase transitions. Indeed, for the usual case, the dominant interaction is repulsive whereas for the reentrant case we encounter an attractive interaction. We show that in the reentrant phase transition case, the small black holes behave like a bosonic gas whereas in the usual phase transition case, they behave like a quantum anyon gas.

Energy harvesting with stacked dielectric elastomer transducers: Nonlinear theory, optimization, and linearized scaling law

NASA Astrophysics Data System (ADS)

Tutcuoglu, A.; Majidi, C.

2014-12-01

Using principles of damped harmonic oscillation with continuous media, we examine electrostatic energy harvesting with a "soft-matter" array of dielectric elastomer (DE) transducers. The array is composed of infinitely thin and deformable electrodes separated by layers of insulating elastomer. During vibration, it deforms longitudinally, resulting in a change in the capacitance and electrical enthalpy of the charged electrodes. Depending on the phase of electrostatic loading, the DE array can function as either an actuator that amplifies small vibrations or a generator that converts these external excitations into electrical power. Both cases are addressed with a comprehensive theory that accounts for the influence of viscoelasticity, dielectric breakdown, and electromechanical coupling induced by Maxwell stress. In the case of a linearized Kelvin-Voigt model of the dielectric, we obtain a closed-form estimate for the electrical power output and a scaling law for DE generator design. For the complete nonlinear model, we obtain the optimal electrostatic voltage input for maximum electrical power output.

Class III dento-skeletal anomalies: rotational growth and treatment timing.

PubMed

Mosca, G; Grippaudo, C; Marchionni, P; Deli, R

2006-03-01

The interception of a Class III malocclusion requires a long-term growth prediction in order to estimate the subject's evolution from the prepubertal phase to adulthood. The aim of this retrospective longitudinal study was to highlight the differences in facial morphology in relation to the direction of mandibular growth in a sample of subjects with Class III skeletal anomalies divided on the basis of their Petrovic's auxological categories and rotational types. The study involved 20 patients (11 females and 9 males) who started therapy before reaching their pubertal peak and were followed up for a mean of 4.3 years (range: 3.9-5.5 years). Despite the small sample size, the definition of the rotational type of growth was the main diagnostic element for setting the correct individualised therapy. We therefore believe that the observation of a larger sample would reinforce the diagnostic-therapeutic validity of Petrovic's auxological categories, allow an evaluation off all rotational types, and improve the statistical significance of the results obtained.

Quasiparticle Excitations in the Superconducting State of FeSe Probed by Thermal Hall Conductivity in the Vicinity of the BCS-BEC Crossover

NASA Astrophysics Data System (ADS)

Watashige, Tatsuya; Arsenijević, Stevan; Yamashita, Takuya; Terazawa, Daiki; Onishi, Takafumi; Opherden, Lars; Kasahara, Shigeru; Tokiwa, Yoshifumi; Kasahara, Yuichi; Shibauchi, Takasada; von Löhneysen, Hilbert; Wosnitza, Jochen; Matsuda, Yuji

2017-01-01

There is growing evidence that the superconducting semimetal FeSe (Tc ˜ 8 K) is in the crossover regime between weak-coupling Bardeen-Cooper-Schrieffer (BCS) and strong-coupling Bose-Einstein-condensate (BEC) limits. We report on longitudinal and transverse thermal conductivities, κxx and κxy, respectively, in magnetic fields up to 20 T. The field dependences of κxx and κxy imply that a highly anisotropic small superconducting gap forms at the electron Fermi-surface pocket whereas a more isotropic and larger gap forms at the hole pocket. Below ˜1.0 K, both κxx and κxy exhibit distinct anomalies (kinks) at the upper critical field Hc2 and at a field H* slightly below Hc2. The analysis of the thermal Hall angle (κxy/κxx) indicates a change of the quasiparticle scattering rate at H*. These results provide strong support to the previous suggestion that above H* a distinct field-induced superconducting phase emerges with an unprecedented large spin imbalance.

Association of Physical Activity and Sedentary Behavior With Psychological Well-Being Among Japanese Children: A Two-Year Longitudinal Study.

PubMed

Ishii, Kaori; Shibata, Ai; Adachi, Minoru; Oka, Koichiro

2016-10-01

Data on the effect of increased or decreased physical activity on children's psychological status are scarce, and effect sizes are small. This study conducted two-year longitudinal research to identify associations between physical activity, sedentary behavior, and psychological well-being in Japanese school children through a mail survey completed by 292 children aged 6-12 years. Data on sociodemographics, physical activity, sedentary behavior on weekdays and the weekend, and psychometrics (self-efficacy, anxiety, and behavioral/emotional problems) were collected using a self-reported questionnaire. A logistic regression analysis was performed, calculating odds ratios for physical activity, psychometrics, and baseline age and physical activity and sedentary behavior changes. For boys, a negative association was found between increased physical activity outside school and maintained or improved self-efficacy as opposed to a positive association in girls. Increased sedentary behavior on weekdays and long periods of sedentary behavior on weekends were associated with maintained or improved behavioral/emotional problems in girls only. This two-year longitudinal study is the first of its kind conducted in Japan. Although effect sizes were small, these results may nevertheless assist in intervention development to promote psychological well-being. © The Author(s) 2016.

Effect of width of incident Gaussian beam on the longitudinal shifts and distortion in the reflected beam

NASA Astrophysics Data System (ADS)

Ziauddin; Qamar, Sajid

2014-05-01

Control of the longitudinal shifts, i.e., spatial and angular Goos-Hänchen (GH) shifts, is revisited to study the effect of width of incident Gaussian beam on the shifts and distortion in the reflected beam. The beam is incident on a cavity consisted of atomic medium where each four-level atom follows N-type atom-field configuration. The atom-field interaction leads to Raman gain process which has been used earlier to observe a significant enhancement of the negative group index, i.e., in the range -103 to -104 for 23Na condensate [G.S. Agarwal, S. Dasgupta, Phys. Rev. A 70 (2004) 023802]. The negative and positive longitudinal shifts could be observed in the reflected light corresponding to the anomalous and normal dispersions of the intracavity medium, respectively. It is observed that the shifts are relatively large for small range of beam width and these became small for large width of the incident beam. It is also noticed that the magnitudes of spatial and angular GH shifts behave differently when the beam width increases. Further, distortion in the reflected beam decreases with an increase in beam width.

Distribution of Rb atoms on the antirelaxation RbH coating

NASA Astrophysics Data System (ADS)

Zhang, Yi; Wang, Zhiguo; Xia, Tao

2017-04-01

We observe the extension of relaxation time of 131Xe with RbH coating, and compare the different depositions of Rb atoms on the inner surface of the vapor cell with and without RbH coating respectively to research the mechanism of coating prolongation. From the 5*5 um2 images of microscopy, we find that on the bare glass surface the Rb atoms form large random separated islands, and to the contrary they deposite as many regular longitudinal stripe of small islands on the RbH coating. We attribute these different distributions to the different molecular interactions between RbH coating and bare glass to Rb atom and build a simple rational physical model to explain this phenomenon. On the one hand, the small islands, or in other words, the relative uniform distribution on RbH coating may result from the relative stronger interaction of Rb to RbH than to the bare glass. On the other hand, the regular longitudinal stripe may stem from the grain boundaries which is related to the macroscopic shape of the vapor cell. And this longitudinal distribution can generate cylindrically electric gradient as used in some theoretically references before.

Spin-lattice relaxation-rate anomaly at structural phase transitions

NASA Astrophysics Data System (ADS)

Levanyuk, A. P.; Minyukov, S. A.; Etrillard, J.; Toudic, B.

1997-12-01

The theory of spin-lattice relaxation (SLR)-rate anomaly at structural phase transitions proposed about 30 years ago is reconsidered taking into account that knowledge about the relevant lattice response functions has changed considerably. We use both the results of previous authors and perform original calculations of the response functions when it is necessary. We consider displacive systems and use the perturbation theory to treat the lattice anharmonicities in a broad temperature region whenever possible. Some comments about the order-disorder systems are made as well. The possibility of linear coupling of the order parameter and the resonance frequency is always assumed. It is found that in the symmetrical phase the anomaly is due to the one-phonon processes, the anomalous part being proportional to either (T-Tc)-1 or (T-Tc)-1/2 depending on some condition on the soft-mode dispersion. In both cases the value of the SLR rate at the boundary of applicabity of the theory (close to the phase transition) is estimated to be 102-103 times more than the typical value of the SLR rate in an ideal crystal. An essential specific feature of the nonsymmetrical phase is appearance of third-order anharmonicities that are well known to lead to a low-frequency dispersion of the order-parameter damping constant. We have found that this constant exhibits, in addition, a strong wave-vector dispersion, so that the damping constant determing the SLR rate is quite different from that at zero wave vector. In the case of two-component order parameter the damping constant for the component with nonzero equilibrium value is different from that for the other component, the difference is of the same order of magnitude as the damping constants themselves. In the case of the incommensurate phase a part of the mentioned third-order anharmonicity is responsible for longitudinal-transversal interaction that is well known to influence the static longitudinal response function. We calculate as well the dynamic response function to find that for the SLR calculations the imaginary part is of main importance. Due to this interaction the longitudinal SLR rate acquires a dependence on the Larmor frequency. This dependence is however, fairly weak: a logarithmic one. The implications of the obtained results for interpretation of the experimental data on SLR in incommensurate phase are discussed as well.

Improving Causal Inferences in Meta-analyses of Longitudinal Studies: Spanking as an Illustration.

PubMed

Larzelere, Robert E; Gunnoe, Marjorie Lindner; Ferguson, Christopher J

2018-05-24

To evaluate and improve the validity of causal inferences from meta-analyses of longitudinal studies, two adjustments for Time-1 outcome scores and a temporally backwards test are demonstrated. Causal inferences would be supported by robust results across both adjustment methods, distinct from results run backwards. A systematic strategy for evaluating potential confounds is also introduced. The methods are illustrated by assessing the impact of spanking on subsequent externalizing problems (child age: 18 months to 11 years). Significant results indicated a small risk or a small benefit of spanking, depending on the adjustment method. These meta-analytic methods are applicable for research on alternatives to spanking and other developmental science topics. The underlying principles can also improve causal inferences in individual studies. © 2018 Society for Research in Child Development.

Structural nested mean models for assessing time-varying effect moderation.

PubMed

Almirall, Daniel; Ten Have, Thomas; Murphy, Susan A

2010-03-01

This article considers the problem of assessing causal effect moderation in longitudinal settings in which treatment (or exposure) is time varying and so are the covariates said to moderate its effect. Intermediate causal effects that describe time-varying causal effects of treatment conditional on past covariate history are introduced and considered as part of Robins' structural nested mean model. Two estimators of the intermediate causal effects, and their standard errors, are presented and discussed: The first is a proposed two-stage regression estimator. The second is Robins' G-estimator. The results of a small simulation study that begins to shed light on the small versus large sample performance of the estimators, and on the bias-variance trade-off between the two estimators are presented. The methodology is illustrated using longitudinal data from a depression study.

Self-injection of electrons in a laser-wakefield accelerator by using longitudinal density ripple

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dahiya, Deepak; Sharma, A. K.; Sajal, Vivek

By introducing a longitudinal density ripple (periodic modulation in background plasma density), we demonstrate self-injection of electrons in a laser-wakefield accelerator. The wakefield driven plasma wave, in presence of density ripple excites two side band waves of same frequency but different wave numbers. One of these side bands, having smaller phase velocity compared to wakefield driven plasma wave, preaccelerates the background plasma electrons. Significant number of these preaccelerated electrons get trapped in the laser-wakefield and further accelerated to higher energies.

Numerical Simulation of the Freeze-Thaw Behavior of Mortar Containing Deicing Salt Solution

PubMed Central

Esmaeeli, Hadi S.; Farnam, Yaghoob; Bentz, Dale P.; Zavattieri, Pablo D.; Weiss, Jason

2016-01-01

This paper presents a one-dimensional finite difference model that is developed to describe the freeze-thaw behavior of an air-entrained mortar containing deicing salt solution. A phenomenological model is used to predict the temperature and the heat flow for mortar specimens during cooling and heating. Phase transformations associated with the freezing/melting of water/ice or transition of the eutectic solution from liquid to solid are included in this phenomenological model. The lever rule is used to calculate the quantity of solution that undergoes the phase transformation, thereby simulating the energy released/absorbed during phase transformation. Undercooling and pore size effects are considered in the numerical model. To investigate the effect of pore size distribution, this distribution is considered using the Gibbs-Thomson equation in a saturated mortar specimen. For an air-entrained mortar, the impact of considering pore size (and curvature) on freezing was relatively insignificant; however the impact of pore size is much more significant during melting. The fluid inside pores smaller than 5 nm (i.e., gel pores) has a relatively small contribution in the macroscopic freeze-thaw behavior of mortar specimens within the temperature range used in this study (i.e., +24 °C to −35 °C), and can therefore be neglected for the macroscopic freeze-thaw simulations. A heat sink term is utilized to simulate the heat dissipation during phase transformations. Data from experiments performed using a low-temperature longitudinal guarded comparative calorimeter (LGCC) on mortar specimens fully saturated with various concentration NaCl solutions or partially saturated with water is compared to the numerical results and a promising agreement is generally obtained. PMID:28082830

Numerical Simulation of the Freeze-Thaw Behavior of Mortar Containing Deicing Salt Solution.

PubMed

Esmaeeli, Hadi S; Farnam, Yaghoob; Bentz, Dale P; Zavattieri, Pablo D; Weiss, Jason

2017-02-01

This paper presents a one-dimensional finite difference model that is developed to describe the freeze-thaw behavior of an air-entrained mortar containing deicing salt solution. A phenomenological model is used to predict the temperature and the heat flow for mortar specimens during cooling and heating. Phase transformations associated with the freezing/melting of water/ice or transition of the eutectic solution from liquid to solid are included in this phenomenological model. The lever rule is used to calculate the quantity of solution that undergoes the phase transformation, thereby simulating the energy released/absorbed during phase transformation. Undercooling and pore size effects are considered in the numerical model. To investigate the effect of pore size distribution, this distribution is considered using the Gibbs-Thomson equation in a saturated mortar specimen. For an air-entrained mortar, the impact of considering pore size (and curvature) on freezing was relatively insignificant; however the impact of pore size is much more significant during melting. The fluid inside pores smaller than 5 nm (i.e., gel pores) has a relatively small contribution in the macroscopic freeze-thaw behavior of mortar specimens within the temperature range used in this study (i.e., +24 °C to -35 °C), and can therefore be neglected for the macroscopic freeze-thaw simulations. A heat sink term is utilized to simulate the heat dissipation during phase transformations. Data from experiments performed using a low-temperature longitudinal guarded comparative calorimeter (LGCC) on mortar specimens fully saturated with various concentration NaCl solutions or partially saturated with water is compared to the numerical results and a promising agreement is generally obtained.

A Longitudinal Assessment of Sleep Timing, Circadian Phase, and Phase Angle of Entrainment across Human Adolescence

PubMed Central

Crowley, Stephanie J.; Van Reen, Eliza; LeBourgeois, Monique K.; Acebo, Christine; Tarokh, Leila; Seifer, Ronald; Barker, David H.; Carskadon, Mary A.

2014-01-01

The aim of this descriptive analysis was to examine sleep timing, circadian phase, and phase angle of entrainment across adolescence in a longitudinal study design. Ninety-four adolescents participated; 38 (21 boys) were 9–10 years (“younger cohort”) and 56 (30 boys) were 15–16 years (“older cohort”) at the baseline assessment. Participants completed a baseline and then follow-up assessments approximately every six months for 2.5 years. At each assessment, participants wore a wrist actigraph for at least one week at home to measure self-selected sleep timing before salivary dim light melatonin onset (DLMO) phase – a marker of the circadian timing system – was measured in the laboratory. Weekday and weekend sleep onset and offset and weekend-weekday differences were derived from actigraphy. Phase angles were the time durations from DLMO to weekday sleep onset and offset times. Each cohort showed later sleep onset (weekend and weekday), later weekend sleep offset, and later DLMO with age. Weekday sleep offset shifted earlier with age in the younger cohort and later in the older cohort after age 17. Weekend-weekday sleep offset differences increased with age in the younger cohort and decreased in the older cohort after age 17. DLMO to sleep offset phase angle narrowed with age in the younger cohort and became broader in the older cohort. The older cohort had a wider sleep onset phase angle compared to the younger cohort; however, an age-related phase angle increase was seen in the younger cohort only. Individual differences were seen in these developmental trajectories. This descriptive study indicated that circadian phase and self-selected sleep delayed across adolescence, though school-day sleep offset advanced until no longer in high school, whereupon offset was later. Phase angle changes are described as an interaction of developmental changes in sleep regulation interacting with psychosocial factors (e.g., bedtime autonomy). PMID:25380248

7 CFR 3403.4 - Three-phase program.

Code of Federal Regulations, 2012 CFR

2012-01-01

... AGRICULTURE SMALL BUSINESS INNOVATION RESEARCH GRANTS PROGRAM Program Description § 3403.4 Three-phase program. The Small Business Innovation Research Grants Program is carried out in three separate phases...

7 CFR 3403.4 - Three-phase program.

Code of Federal Regulations, 2014 CFR

2014-01-01

... AGRICULTURE SMALL BUSINESS INNOVATION RESEARCH GRANTS PROGRAM Program Description § 3403.4 Three-phase program. The Small Business Innovation Research Grants Program is carried out in three separate phases...

7 CFR 3403.4 - Three-phase program.

Code of Federal Regulations, 2013 CFR

2013-01-01

... AGRICULTURE SMALL BUSINESS INNOVATION RESEARCH GRANTS PROGRAM Program Description § 3403.4 Three-phase program. The Small Business Innovation Research Grants Program is carried out in three separate phases...

Phase-front measurements of an injection-locked AlGaAs laser-diode array

NASA Technical Reports Server (NTRS)

Cornwell, Donald M., Jr.; Rall, Jonathan A. R.; Abshire, James B.

1989-01-01

The phase-front quality of the primary spatial lobe emitted from an injection-locked gain-guided AlGaAs laser-diode array is measured by using an equal-path, phase-shifting Mach-Zehnder interferometer. Root-mean-square phase errors of 0.037 + or - 0.003 wave are measured for the single spatial lobe, which contained 240-mW cw output power in a single longitudinal mode. This phase-front quality corresponds to a Strehl ratio of S = 0.947, which results in a 0.23-dB power loss from the single lobe's ideal diffraction-limited power. These values are comparable with those measured for single-stripe index-guided AlGaAs lasers.

Basilar membrane vibration is not involved in the reverse propagation of otoacoustic emissions

PubMed Central

He, W.; Ren, T.

2013-01-01

To understand how the inner ear-generated sound, i.e., otoacoustic emission, exits the cochlea, we created a sound source electrically in the second turn and measured basilar membrane vibrations at two longitudinal locations in the first turn in living gerbil cochleae using a laser interferometer. For a given longitudinal location, electrically evoked basilar membrane vibrations showed the same tuning and phase lag as those induced by sounds. For a given frequency, the phase measured at a basal location led that at a more apical location, indicating that either an electrical or an acoustical stimulus evoked a forward travelling wave. Under postmortem conditions, the electrically evoked emissions showed no significant change while the basilar membrane vibration nearly disappeared. The current data indicate that basilar membrane vibration was not involved in the backward propagation of otoacoustic emissions and that sounds exit the cochlea probably through alternative media, such as cochlear fluids. PMID:23695199

Numerical and neutron diffraction measurement of residual stress distribution in dissimilar weld

DOE PAGES

Eisazadeh, Hamid; Bunn, Jeffrey R.; Aidun, Daryush K.

2017-01-01

In this study, a model considering an asymmetric power heat distribution, temperature-dependent material properties, strain hardening and phase transformation was developed to predict temperature field and residual stress distribution in GTA dissimilar weld between austenitic stainless steel (304) and low carbon steel (1018). The effect of martensite formation on longitudinal and transverse residual stress distributions were investigated using both FE model and neutron diffraction measurement. The results indicate that martensitic phase has a significant influence on both residual stress components, i.e., transverse and longitudinal, and it not only can change the distribution shape of residual stress near the weld centermore » line but, also, can alter the peak value of the residual stresses. The calculated temperature and weld zone profile were in agreement with the experimental results. Favorable general agreement was also found between the calculated residual stress distribution and residual stress measurements by the neutron diffraction method.« less

Numerical and neutron diffraction measurement of residual stress distribution in dissimilar weld

DOE Office of Scientific and Technical Information (OSTI.GOV)

Eisazadeh, Hamid; Bunn, Jeffrey R.; Aidun, Daryush K.

In this study, a model considering an asymmetric power heat distribution, temperature-dependent material properties, strain hardening and phase transformation was developed to predict temperature field and residual stress distribution in GTA dissimilar weld between austenitic stainless steel (304) and low carbon steel (1018). The effect of martensite formation on longitudinal and transverse residual stress distributions were investigated using both FE model and neutron diffraction measurement. The results indicate that martensitic phase has a significant influence on both residual stress components, i.e., transverse and longitudinal, and it not only can change the distribution shape of residual stress near the weld centermore » line but, also, can alter the peak value of the residual stresses. The calculated temperature and weld zone profile were in agreement with the experimental results. Favorable general agreement was also found between the calculated residual stress distribution and residual stress measurements by the neutron diffraction method.« less

Longitudinal decline in structural networks predicts dementia in cerebral small vessel disease

PubMed Central

Lawrence, Andrew J.; Zeestraten, Eva A.; Benjamin, Philip; Lambert, Christian P.; Morris, Robin G.; Barrick, Thomas R.

2018-01-01

Objective To determine whether longitudinal change in white matter structural network integrity predicts dementia and future cognitive decline in cerebral small vessel disease (SVD). To investigate whether network disruption has a causal role in cognitive decline and mediates the association between conventional MRI markers of SVD with both cognitive decline and dementia. Methods In the prospective longitudinal SCANS (St George's Cognition and Neuroimaging in Stroke) Study, 97 dementia-free individuals with symptomatic lacunar stroke were followed with annual MRI for 3 years and annual cognitive assessment for 5 years. Conversion to dementia was recorded. Structural networks were constructed from diffusion tractography using a longitudinal registration pipeline, and network global efficiency was calculated. Linear mixed-effects regression was used to assess change over time. Results Seventeen individuals (17.5%) converted to dementia, and significant decline in global cognition occurred (p = 0.0016). Structural network measures declined over the 3-year MRI follow-up, but the degree of change varied markedly between individuals. The degree of reductions in network global efficiency was associated with conversion to dementia (B = −2.35, odds ratio = 0.095, p = 0.00056). Change in network global efficiency mediated much of the association of conventional MRI markers of SVD with cognitive decline and progression to dementia. Conclusions Network disruption has a central role in the pathogenesis of cognitive decline and dementia in SVD. It may be a useful disease marker to identify that subgroup of patients with SVD who progress to dementia. PMID:29695593

Transition from convective to absolute Raman instability via the longitudinal relativistic effect by using Vlasov-Maxwell simulations

NASA Astrophysics Data System (ADS)

Wang, Q.; Liu, Z. J.; Zheng, C. Y.; Xiao, C. Z.; Feng, Q. S.; Zhang, H. C.; He, X. T.

2018-01-01

The longitudinal relativistic effect on stimulated Raman backscattering (SRBS) is investigated by using one-dimensional (1D) Vlasov-Maxwell simulations. Using a short backscattered light seed pulse with a very small amplitude, the linear gain spectra of SRBS in the strongly convective regime is presented by combining the relativistic and non-relativistic 1D Vlasov-Maxwell simulations, which is in agreement with the steady-state linear theory. More interestingly, by considering transition from convective to absolute instability due to electron trapping, we successfully predict the critical duration of the seed which can just trigger the kinetic inflation of the excited SRBS after the seed leaves the simulation box. The critical duration in the relativistic case is much shorter than that in the nonrelativistic case, which indicates that the kinetic inflation more easily occurs in the relativistic case than in the nonrelativistic case. In the weakly convective regime, the transition from convective to absolute instability for SRBS can directly occur in the linear regime due to the longitudinal relativistic modification. For the same pump, our simulations first demonstrate that the SRBS excited by a short and small seed pulse is a convective instability in the nonrelativistic case but becomes an absolute instability due to the decrease of the linear Landau damping from the longitudinal relativistic modification in the relativistic case. In more detail, the growth rate of the backscattered light is also in excellent agreement with theoretical prediction.

Impact of demographics and disease progression on the relationship between glucose and HbA1c.

PubMed

Claussen, Anetta; Møller, Jonas B; Kristensen, Niels R; Klim, Søren; Kjellsson, Maria C; Ingwersen, Steen H; Karlsson, Mats O

2017-06-15

Several studies have shown that the relationship between mean plasma glucose (MPG) and glycated haemoglobin (HbA1c) may vary across populations. Especially race has previously been referred to shift the regression line that links MPG to HbA1c at steady-state (Herman & Cohen, 2012). To assess the influence of demographic and disease progression-related covariates on the intercept of the estimated linear MPG-HbA1c relationship in a longitudinal model. Longitudinal patient-level data from 16 late-phase trials in type 2 diabetes with a total of 8927 subjects was used to study covariates for the relationship between MPG and HbA1c. The analysed covariates included age group, BMI, gender, race, diabetes duration, and pre-trial treatment. Differences between trials were taken into account by estimating a trial-to-trial variability component. Participants included 47% females and 20% above 65years. 77% were Caucasian, 9% were Asian, 5% were Black and the remaining 9% were analysed together as other races. Estimates of the change in the intercept of the MPG-HbA1c relationship due to the mentioned covariates were determined using a longitudinal model. The analysis showed that pre-trial treatment with insulin had the most pronounced impact associated with a 0.34% higher HbA1c at a given MPG. However, race, diabetes duration and age group also had an impact on the MPG-HbA1c relationship. Our analysis shows that the relationship between MPG and HbA1c is relatively insensitive to covariates, but shows small variations across populations, which may be relevant to take into account when predicting HbA1c response based on MPG measurements in clinical trials. Copyright © 2017 Elsevier B.V. All rights reserved.

The Impact of Changes in the TOEFL® Examination on Teaching and Learning in Central and Eastern Europe: Phase 2, Coping with Change. TOEFL iBT Research Report. TOEFL iBT-05. ETS RR-08-37

ERIC Educational Resources Information Center

Wall, Dianne; Horák, Tania

2008-01-01

The aim of this report is to present the findings of the second phase in a longitudinal study of the impact of changes in the TOEFL® test on teaching and learning in test preparation classrooms. The focus of this phase was to monitor six teachers from five countries in Central and Eastern Europe as they received news about changes in the TOEFL and…

Electron transport in zinc-blende wurtzite biphasic gallium nitride nanowires and GaNFETs

DOE PAGES

Jacobs, Benjamin W.; Ayres, Virginia M.; Stallcup, Richard E.; ...

2007-10-19

Two-point and four-point probe electrical measurements of a biphasic gallium nitride nanowire and current–voltage characteristics of a gallium nitride nanowire based field effect transistor are reported. The biphasic gallium nitride nanowires have a crystalline homostructure consisting of wurtzite and zinc-blende phases that grow simultaneously in the longitudinal direction. There is a sharp transition of one to a few atomic layers between each phase. Here, all measurements showed high current densities. Evidence of single-phase current transport in the biphasic nanowire structure is discussed.

Microscopic theory of longitudinal sound velocity in charge ordered manganites.

PubMed

Rout, G C; Panda, S

2009-10-14

A microscopic theory of longitudinal sound velocity in a manganite system is reported here. The manganite system is described by a model Hamiltonian consisting of charge density wave (CDW) interaction in the e(g) band, an exchange interaction between spins of the itinerant e(g) band electrons and the core t(2g) electrons, and the Heisenberg interaction of the core level spins. The magnetization and the CDW order parameters are considered within mean-field approximations. The phonon Green's function was calculated by Zubarev's technique and hence the longitudinal velocity of sound was finally calculated for the manganite system. The results show that the elastic spring involved in the velocity of sound exhibits strong stiffening in the CDW phase with a decrease in temperature as observed in experiments.

Use of Wedge Absorbers in MICE

DOE Office of Scientific and Technical Information (OSTI.GOV)

Neuffer, D.; Summers, D.; Mohayai, T.

2017-03-01

Wedge absorbers are needed to obtain longitudinal cooling in ionization cooling. They also can be used to obtain emittance exchanges between longitudinal and transverse phase space. There can be large exchanges in emittance, even with single wedges. In the present note we explore the use of wedge absorbers in the MICE experiment to obtain transverse–longitudinal emittance exchanges within present and future operational conditions. The same wedge can be used to explore “direct” and “reverse” emittance exchange dynamics, where direct indicates a configuration that reduces momentum spread and reverse is a configuration that increases momentum spread. Analytical estimated and ICOOL andmore » G4BeamLine simulations of the exchanges at MICE parameters are presented. Large exchanges can be obtained in both reverse and direct configurations.« less

IBS and possible luminosity improvement for RHIC operation below transition energy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fedotov,A.V.

There is a strong interest in low-energy RHIC collisions in the energy range below present RHIC transition energy. These collisions win help to answer one of the key questions in the field of QCD about the existence and location of a critical point on the QCD phase diagram. For such low-energy RHIC operation, particle losses from the RF bucket are of particular concern since the longitudinal beam size is comparable to the existing RF bucket at low energies. In this paper, we explore an Intrabeam Scattering (IBS) feature below transition energy that drives the transverse and longitudinal beam temperatures towardsmore » equilibrium to see whether we can minimize longitudinal diffusion due to IBS and predict some luminosity improvement for the low-energy RHIC project.« less

Implementing Technology with Industrial Community: The SBIR Example

NASA Technical Reports Server (NTRS)

Ghuman, Parminder

2005-01-01

The Earth-Sun system Technology Office (ESTO) works with Small Business Innovation Research (SBIR) and Small Business Technology Transfer (STTR) programs to supplement its own technology development program. The SBIR/STTR program is a highly competitive program that encourages small business to explore their technological potential to fulfill technology needs identified by ESTO. SBIR program has three phases. The Phase 1 contracts last for 6 months with a maximum funding of $70,000, and Phase 2 contracts last for 24 months with a maximum funding of $600,000. For Phase 3, the small business must find funding in the private sector or other non-SBIR federal agency funding. During this phase ESTO evaluates Phase 2 graduates and selects those that need to be further developed for airborne or spaceflight demonstration and provides funding. This paper will discuss the all three phases in and role of ESTO in this program.

Electron charge and spin delocalization revealed in the optically probed longitudinal and transverse spin dynamics in n -GaAs

NASA Astrophysics Data System (ADS)

Belykh, V. V.; Kavokin, K. V.; Yakovlev, D. R.; Bayer, M.

2017-12-01

The evolution of the electron spin dynamics as consequence of carrier delocalization in n -type GaAs is investigated by the recently developed extended pump-probe Kerr/Faraday rotation spectroscopy. We find that isolated electrons localized on donors demonstrate a prominent difference between the longitudinal and transverse spin relaxation rates in a magnetic field, which is almost absent in the metallic phase. The inhomogeneous transverse dephasing time T2* of the spin ensemble strongly increases upon electron delocalization as a result of motional narrowing that can be induced by increasing either the donor concentration or the temperature. An unexpected relation between T2* and the longitudinal spin relaxation time T1 is found, namely, that their product is about constant, as explained by the magnetic field effect on the spin diffusion. We observe a two-stage longitudinal spin relaxation, which suggests the establishment of spin temperature in the system of exchange-coupled donor-bound electrons.

Phase Zero Contracting Operations-Strategic and Integrative Planning for Contingency and Expeditionary Operations

DTIC Science & Technology

2013-10-01

349–372 Phase Zero Contracting Operations (PZCO) FIGURE 4. CONTRACTING PHASE ZERO: PLAN, EXERCISE, REHEARSE, AND SYNCHRONIZE Note. BPA = Blanket...More Robust Construction Supplies; Oce Equipment; Quality of Life; and Morale, Welfare, and Recreation PO/TO/DO/ BPA Small Purchase Standard Vehicles PO...TO/DO/ BPA Small Purchase Standard Vehicles PO/TO/DO/ BPA Small Purchase Standard Vehicles PO/TO/DO/ BPA Small Purchase Food, Water, Billeting, Hygiene

Estimation of strength parameters of small-bore metal-polymer pipes

NASA Astrophysics Data System (ADS)

Shaydakov, V. V.; Chernova, K. V.; Penzin, A. V.

2018-03-01

The paper presents results from a set of laboratory studies of strength parameters of small-bore metal-polymer pipes of type TG-5/15. A wave method was used to estimate the provisional modulus of elasticity of the metal-polymer material of the pipes. Longitudinal deformation, transverse deformation and leak-off pressure were determined experimentally, with considerations for mechanical damage and pipe bend.

Right ventricular function after repair of tetralogy of Fallot: a comparison between bovine pericardium and porcine small intestinal extracellular matrix.

PubMed

Naik, Ronak; Johnson, Jason; Kumar, T K S; Philip, Ranjit; Boston, Umar; Knott-Craig, Christopher J

2017-05-29

The porcine small intestinal extracellular matrix reportedly has the potential to differentiate into viable myocardial cells. When used in tetralogy of Fallot repair, it may improve right ventricular function. We evaluated right ventricular function after repair of tetralogy of Fallot with extracellular matrix versus bovine pericardium. Subjects with non-transannular repair of tetralogy of Fallot with at least 1 year of follow-up were selected. The extracellular matrix and bovine pericardium groups were compared. We used three-dimensional right ventricular ejection fraction, right ventricle global longitudinal strain, and tricuspid annular plane systolic excursion to assess right ventricular function. The extracellular matrix group had 11 patients, whereas the bovine pericardium group had 10 patients. No differences between the groups were found regarding sex ratio, age at surgery, and cardiopulmonary bypass time. The follow-up period was 28±12.6 months in the extracellular matrix group and 50.05±17.6 months in the bovine pericardium group (p=0.001). The mean three-dimensional right ventricular ejection fraction (55.7±5.0% versus 55.3±5.2%, p=0.73), right ventricular global longitudinal strain (-18.5±3.0% versus -18.0±2.2%, p=0.44), and tricuspid annular plane systolic excursions (1.59±0.16 versus 1.59±0.2, p=0.93) were similar in the extracellular matrix group and in the bovine pericardium group, respectively. Right ventricular global longitudinal strain in healthy children is reported at -29±3% in literature. In a small cohort of the patients undergoing non-transannular repair of tetralogy of Fallot, there was no significant difference in right ventricular function between groups having extracellular matrix versus bovine pericardium patches followed-up for more than 1 year. Lower right ventricular longitudinal strain noted in both the groups compared to healthy children.

Information fusion based optimal control for large civil aircraft system.

PubMed

Zhen, Ziyang; Jiang, Ju; Wang, Xinhua; Gao, Chen

2015-03-01

Wind disturbance has a great influence on landing security of Large Civil Aircraft. Through simulation research and engineering experience, it can be found that PID control is not good enough to solve the problem of restraining the wind disturbance. This paper focuses on anti-wind attitude control for Large Civil Aircraft in landing phase. In order to improve the riding comfort and the flight security, an information fusion based optimal control strategy is presented to restrain the wind in landing phase for maintaining attitudes and airspeed. Data of Boeing707 is used to establish a nonlinear mode with total variables of Large Civil Aircraft, and then two linear models are obtained which are divided into longitudinal and lateral equations. Based on engineering experience, the longitudinal channel adopts PID control and C inner control to keep longitudinal attitude constant, and applies autothrottle system for keeping airspeed constant, while an information fusion based optimal regulator in the lateral control channel is designed to achieve lateral attitude holding. According to information fusion estimation, by fusing hard constraint information of system dynamic equations and the soft constraint information of performance index function, optimal estimation of the control sequence is derived. Based on this, an information fusion state regulator is deduced for discrete time linear system with disturbance. The simulation results of nonlinear model of aircraft indicate that the information fusion optimal control is better than traditional PID control, LQR control and LQR control with integral action, in anti-wind disturbance performance in the landing phase. Copyright © 2014 ISA. Published by Elsevier Ltd. All rights reserved.

Metallographic Characterization of Wrought Depleted Uranium

DOE Office of Scientific and Technical Information (OSTI.GOV)

Forsyth, Robert Thomas; Hill, Mary Ann

Metallographic characterization was performed on wrought depleted uranium (DU) samples taken from the longitudinal and transverse orientations from specific locations on two specimens. Characterization of the samples included general microstructure, inclusion analysis, grain size analysis, and microhardness testing. Comparisons of the characterization results were made to determine any differences based on specimen, sample orientation, or sample location. In addition, the characterization results for the wrought DU samples were also compared with data obtained from the metallographic characterization of cast DU samples previously characterized. No differences were observed in microstructure, inclusion size, morphology, and distribution, or grain size in regard tomore » specimen, location, or orientation for the wrought depleted uranium samples. However, a small difference was observed in average hardness with regard to orientation at the same locations within the same specimen. The longitudinal samples were slightly harder than the transverse samples from the same location of the same specimen. This was true for both wrought DU specimens. Comparing the wrought DU sample data with the previously characterized cast DU sample data, distinct differences in microstructure, inclusion size, morphology and distribution, grain size, and microhardness were observed. As expected, the microstructure of the wrought DU samples consisted of small recrystallized grains which were uniform, randomly oriented, and equiaxed with minimal twinning observed in only a few grains. In contrast, the cast DU microstructure consisted of large irregularly shaped grains with extensive twinning observed in most grains. Inclusions in the wrought DU samples were elongated, broken and cracked and light and dark phases were observed in some inclusions. The mean inclusion area percentage for the wrought DU samples ranged from 0.08% to 0.34% and the average density from all wrought DU samples was 1.62E+04/cm 2. Inclusions in the cast DU samples were equiaxed and intact with light and dark phases observed in some inclusions. The mean inclusion area percentage for the cast DU samples ranged from 0.93% to 1.00% and the average density from all wrought DU samples was 2.83E+04/cm 2. The average mean grain area from all wrought DU samples was 141 μm 2 while the average mean grain area from all cast DU samples was 1.7 mm2. The average Knoop microhardness from all wrought DU samples was 215 HK and the average Knoop microhardness from all cast DU samples was 264 HK.« less

Personality at midlife: stability, intrinsic maturation, and response to life events.

PubMed

Costa, P T; Herbst, J H; McCrae, R R; Siegler, I C

2000-12-01

Although developmental theories and popular accounts suggest that midlife is a time of turmoil and change, longitudinal studies of personality traits have generally found stability of rank order and little or no change in mean levels. Using data from 2,274 men and women in their 40s retested after 6 to 9 years, the present study examined two hypotheses: (a) that retest correlations should be no higher than about .60 and (b) that there should be small decreases in Neuroticism, Extraversion, and Openness, and small increases in Agreeableness and Conscientiousness. The study also explored the effects of recalled life events on subsequent personality scores. Results did not support the first hypothesis; uncorrected retest correlations uniformly exceeded .60. This was true for all personality traits, including facets of Agreeableness and Conscientiousness not previously included in longitudinal studies. The hypothesized decreases in Neuroticism, Extraversion, and Openness were found, but Conscientiousness showed a small decrease instead of the predicted increase. Life events in general showed very little influence on the levels of personality traits, although some effects were seen for changes in job and marital status that warrant further research.

Adaptive algorithms to map how brain trauma affects anatomical connectivity in children

NASA Astrophysics Data System (ADS)

Dennis, Emily L.; Prasad, Gautam; Babikian, Talin; Kernan, Claudia; Mink, Richard; Babbitt, Christopher; Johnson, Jeffrey; Giza, Christopher C.; Asarnow, Robert F.; Thompson, Paul M.

2015-12-01

Deficits in white matter (WM) integrity occur following traumatic brain injury (TBI), and often persist long after the visible scars have healed. Heterogeneity in injury types and locations can complicate analyses, making it harder to discover common biomarkers for tracking recovery. Here we apply a newly developed adaptive connectivity method, EPIC (evolving partitions to improve connectomics) to identify differences in structural connectivity that persist longitudinally. This data comes from a longitudinal study, in which we scanned participants (aged 8-19 years) with anatomical and diffusion MRI in both the post-acute and chronic phases (1-6 months and 13-19 months post-injury). To identify patterns of abnormal connectivity, we trained a model on data from 32 TBI patients in the post-acute phase and 45 well-matched healthy controls, reducing an initial 68x68 connectivity matrix to a 14x14 matrix. We then applied this reduced parcellation to the chronic data in participants who had returned for their chronic assessment (21 TBI and 26 healthy controls) and tested for group differences. We found significant differences in two connections, comprising callosal fibers and long anterior-posterior fibers, with the TBI group showing increased fiber density relative to controls. Longitudinal analysis revealed that these were connections that were decreasing over time in the healthy controls, as is a common developmental phenomenon, but they were increasing in the TBI group. While we cannot definitively tell why this may occur with our current data, this study provides targets for longitudinal tracking, and poses questions for future investigation.

Large magnetic to electric field contrast in azimuthally polarized vortex beams generated by a metasurface (Presentation Recording)

NASA Astrophysics Data System (ADS)

Veysi, Mehdi; Guclu, Caner; Capolino, Filippo

2015-09-01

We investigate azimuthally E-polarized vortex beams with enhanced longitudinal magnetic field. Ideally, such beams possess strong longitudinal magnetic field on the beam axis where there is no electric field. First we formulate the electric field vector and the longitudinal magnetic field of an azimuthally E-polarized beam as an interference of right- and left-hand circularly polarized Laguerre Gaussian (LG) beams carrying the orbital angular momentum (OAM) states of -1 and +1, respectively. Then we propose a metasurface design that is capable of converting a linearly polarized Gaussian beam into an azimuthally E-polarized vortex beam with longitudinal magnetic field. The metasurface is composed of a rectangular array of double-layer double split-ring slot elements, though other geometries could be adopted as well. The element is specifically designed to have nearly a 180° transmission phase difference between the two polarization components along two orthogonal axes, similar to the optical axes of a half-wave plate. By locally rotating the optical axes of each metasurface element, the transmission phase profile of the circularly polarized waves over the metasurface can be tailored. Upon focusing of the generated vortex beam through a lens with a numerical aperture of 0.7, a 41-fold enhancement of the magnetic to electric field ratio is achieved on the beam axis with respect to that of a plane wave. Generation of beams with large magnetic field to electric field contrast can find applications in future spectroscopy systems based on magnetic dipole transitions, which are usually much weaker than electric dipole transitions.

Consequences of bounds on longitudinal emittance growth for the design of recirculating linear accelerators

DOE Office of Scientific and Technical Information (OSTI.GOV)

Berg, J. S.

2015-05-03

Recirculating linear accelerators (RLAs) are a cost-effective method for the acceleration of muons for a muon collider in energy ranges from a couple GeV to a few 10s of GeV. Muon beams generally have longitudinal emittances that are large for the RF frequency that is used, and it is important to limit the growth of that longitudinal emittance. This has particular consequences for the arc design of the RLAs. I estimate the longitudinal emittance growth in an RLA arising from the RF nonlinearity. Given an emittance growth limitation and other design parameters, one can then compute the maximum momentum compactionmore » in the arcs. I describe how to obtain an approximate arc design satisfying these requirements based on the deisgn in [1]. Longitudinal dynamics also determine the energy spread in the beam, and this has consequences on the transverse phase advance in the linac. This in turn has consequences for the arc design due to the need to match beta functions. I combine these considerations to discuss design parameters for the acceleration of muons for a collider in an RLA from 5 to 63 GeV.« less

Different experimental results for the influence of immersion angle on the resonant frequency of a quartz crystal microbalance in a liquid phase: with a comment.

PubMed

Shen, Dazhong; Kang, Qi; Li, Xiaoyu; Cai, Hongmei; Wang, Yuandong

2007-06-19

This paper presents different experimental results of the influence of an immersion angle (theta, the angle between the surface of a quartz crystal resonator and the horizon) on the resonant frequency of a quartz crystal microbalance (QCM) sensor exposed one side of its sensing surfaces to liquid. The experimental results show that the immersion angle is an added factor that may influence the frequency of the QCM sensor. This type of influence is caused by variation of the reflection conditions of the longitudinal wave between the QCM sensor and the walls of the detection cell. The frequency shifts, measured by varying theta, are related to the QCM sensor used. When a QCM sensor with a weak longitudinal wave is used, its resonant frequency is nearly independent of theta. But, if a QCM sensor with a strong longitudinal wave is employed, the immersion angle is a potential error source for the measurements performed on the QCM sensor. When the reflection conditions of the longitudinal wave are reduced, the influence of theta on the resonant frequency of the QCM sensor is negligible. The slope of the plot of frequency shifts (deltaF) versus (rho eta)(1/2), the square root of the product of solution density (rho) and viscosity (eta), may be influenced by theta in a single experiment for the QCM sensor with a strong longitudinal wave in low viscous liquids, which can however, be effectively weakened by using the averaged values of reduplicated experiments. In solutions with a large (rho eta)(1/2) region (0-55 wt% sucrose solution as an example, with rho value from 1.00 to 1.26 g cm(-3) and eta value from 0.01 to 0.22 g cm(-1) s(-1), respectively), the slope of the plot of deltaF versus (rho eta)(1/2) is independent of theta even for the QCM sensor with a strong longitudinal wave in a single experiment. The influence of theta on the resonant frequency of the QCM sensor should be taken into consideration in its applications in liquid phase.

Effect of Sm-Rich Phase on Corrosion Behavior of Hot-Extruded AZ31-1.5Sm Magnesium Alloy

NASA Astrophysics Data System (ADS)

Li, Xiao; Hu, Zhi; Yan, Hong; Wu, Xiaoquan; Xie, Hecong; Dong, Zhou

2018-05-01

The effects of Sm on the corrosion and microstructure behavior of hot-extruded AZ31 magnesium alloy were investigated by SEM, TEM, weight loss analysis, and electrochemical measurements. The results indicated that granular Al2Sm phase 4 μm in size in the hot-extruded AZ31 magnesium alloy modified with 1.5 wt.% Sm leads to significant grain refinement. The corrosion rate decreased from 15.98 × 10-4 to 11.19 × 10-4 g cm-2 h-1 in the transverse section and from 8.57 × 10-4 to 6.20 × 10-4 g cm-2 h-1 in the longitudinal section. Compared to the unmodified alloy, the corrosion potential of the Sm-modified alloy in the transverse and longitudinal sections increased by 98 and 62 mV, respectively, and the R ct value (charge transfer resistance) in the transverse and longitudinal sections of the modified alloy increased from 1764 and 1756 to 2928 and 2408 Ω cm2, respectively. The results showed that the corrosion resistance of hot-extruded AZ31 magnesium alloy was significantly improved by Sm addition due to the grain refinement, the decreased dislocation density, and the suppression of micro-galvanic corrosion caused by Al-Sm-(Mn) intermetallic compounds.

'Real-life' study of imatinib therapy in chronic phase-chronic myeloid leukemia: A novel retrospective observational longitudinal analysis.

PubMed

Merante, Serena; Ferretti, Virginia; Elena, Chiara; Calvello, Celeste; Rocca, Barbara; Zappatore, Rita; Cavigliano, Paola; Orlandi, Ester

2017-01-01

Imatinib is a cornerstone of treatment of chronic myeloid leukemia. It remains unclear whether transient treatment discontinuation or dose changes affect outcome and this approach has not yet been approved for use outside clinical trials. We conducted a retrospective single-institution observational study to evaluate factors affecting response in 'real-life' clinical practice in 138 chronic myeloid leukemia patients in chronic phase treated with imatinib. We used a novel longitudinal data analytical model, with a generalized estimating equation model, to study BCR-ABL variation according to continuous standard dose, change in dose or discontinuation; BCR-ABL transcript levels were recorded. Treatment history was subdivided into time periods for which treatment was given at constant dosage (total 483 time periods). Molecular and cytogenetic complete response was observed after 154 (32%) and 358 (74%) time periods, respectively. After adjusting for length of time period, no association between dose and cytogenetic complete response rate was observed. There was a significantly lower molecular complete response rate after time periods at a high imatinib dosage. This statistical approach can identify individual patient variation in longitudinal data collected over time and suggests that changes in dose or discontinuation of therapy could be considered in patients with appropriate biological characteristics.

Longitudinal Relaxation of Ferromagnetic Grains

NASA Astrophysics Data System (ADS)

Würger, Alois

1998-07-01

We study the activated longitudinal dynamics of a small single-domain magnet with uniaxial anisotropy, coupled to quantum noise. The smallest finite eigenvalue λ1 = γ0e-EB/kBT of the relaxation matrix is evaluated in a controlled approximation. For white noise we find γ0~T-1 at moderate temperatures and γ0 = const at very low T. Coupling to elastic waves leads to a prefactor that is linear in T or constant, depending on temperature. At very low T, the discreteness of the energy spectrum is crucial.

Psychological distress through immigration: the two-phase temporal pattern?

PubMed

Ritsner, M; Ponizovsky, A

1999-01-01

A large community sample, cross-sectional and in part longitudinal design, and comparison groups was used to determine the timing of psychological distress among immigrants. A total of 2,378 adult immigrants from the former Soviet Union to Israel completed the self-administered questionnaire Talbieh Brief Distress Inventory. The aggregate levels of distress and six psychological symptoms--obsessiveness, hostility, interpersonal sensitivity, depression, anxiety, and paranoid ideation--were compared at 20 intervals covering 1 to 60 months after resettlement. The level of psychological distress was significantly higher in the immigrants than that of Israeli natives but not in the potential immigrant controls. A two-phase temporal pattern of development of psychological distress was revealed consisting of escalation and reduction phases. The escalation phase was characterized by an increase in distress levels until the 27th month after arrival (a peak) and the reduction phase led to a decline returning to normal levels. The 1-month prevalence rate was 15.6% for the total sample, and for highly distressed subjects it reached 24% at the 27th month after arrival, and it declined to 4% at the 44th month. The time pattern of distress shared males and females, married and divorced/widowed (but not singles), as well as subjects of all age groups (except for immigrants in their forties). The two-phase pattern of distress obtained according to cross-sectional data was indirectly confirmed through a longitudinal way. Claims of early euphoric or distress-free period followed by mental health crisis frequently referred to in the literature on migration was not supported by this study.

How students experience and navigate transitions in undergraduate medical education: an application of Bourdieu's theoretical model.

PubMed

Balmer, Dorene F; Richards, Boyd F; Varpio, Lara

2015-10-01

Using Bourdieu's theoretical model as a lens for analysis, we sought to understand how students experience the undergraduate medical education (UME) milieu, focusing on how they navigate transitions from the preclinical phase, to the major clinical year (MCY), and to the preparation for residency phase. Twenty-two medical students participated in this longitudinal case study. Students had similar preclinical and post-MCY experiences but different MCY experiences (rotational vs. longitudinal tracks). We interviewed students every 6 months in the preclinical phase, mid-way through MCY, and 7-8 months before graduation (101 total interviews). We inductively created codes, iteratively revised codes to best-fit the data, and thematically clustered codes into Bourdieu-informed categories: field (social structures), capital (resources) and habitus (dispositions). We found that students acclimated to shifts in the UME field as they moved through medical school: from medical school itself to the health system and back. To successfully navigate transitions, students learned to secure capital as medical knowledge and social connections in the preclinical and preparation for residency phases, and as reputable patient care and being noticed in the clinical phase. To obtain capital, and be well-positioned for the next phase of training, students consistently relied on dispositions of initiative and flexibility. In summary, students experience the complex context of medical school through a series of transitions. Efforts to improve UME would be well-served by greater awareness of the social structures (field) that students encounter, the resources to which they afford value (capital), and the dispositions which aid acquisition of these resources (habitus).

EVALUATION OF THE FARM MANAGEMENT PHASE OF THE FARM AND HOME MANAGEMENT PROGRAM IN NEW YORK STATE. EXTENSION STUDY, NUMBER 1.

ERIC Educational Resources Information Center

ALEXANDER, FRANK D.; LONGEST, JAMES W.

THE MAIN PURPOSE OF THIS 1956-60 LONGITUDINAL STUDY WAS TO COMPARE CHANGES IN FARM PRACTICES AND RELATED KNOWLEDGE AND IN INCOME AND RELATED BUSINESS FACTORS AMONG 87 PARTICIPANTS (DAIRYMEN) IN THE FARM MANAGEMENT PHASE OF THE NEW YORK STATE FARM AHD HOME MANAGEMENT PROGRAM, WITH THOSE OF A CONTROL GROUP OF 87 WHO DID NOT PARTICIPATE. IN 1956, THE…

Preliminary results toward injection locking of an incoherent laser array

NASA Technical Reports Server (NTRS)

Daher, J.

1986-01-01

The preliminary results of phase locking an incoherent laser array to a master source in an attempt to achieve coherent operation are presented. The techniques necessary to demonstrate phase locking are described along with some topics for future consideration. As expected, the results obtained suggest that injection locking of an array, where the spacing between adjacent longitudinal modes of its elements is significantly larger than the locking bandwidth, may not be feasible.

Comparative Effectiveness of PCI Education's "PCI Reading Program": Phase 2--A Report of a Comparison Group Study in Brevard Public Schools and Miami-Dade County Public Schools. Research Summary

ERIC Educational Resources Information Center

Empirical Education Inc., 2010

2010-01-01

PCI Education sought scientifically based evidence on the comparative effectiveness of the "PCI Reading Program" through a five-year longitudinal study. Phase 1 of the study consisted of a randomized control trial studying the efficacy of the "PCI Reading Program-Level One" that was conducted in the 2007-2008 in Miami-Dade…

Optical testing using the transport-of-intensity equation.

PubMed

Dorrer, C; Zuegel, J D

2007-06-11

The transport-of-intensity equation links the intensity and phase of an optical source to the longitudinal variation of its intensity in the presence of Fresnel diffraction. This equation can be used to provide a simple, accurate spatial-phase measurement for optical testing of flat surfaces. The properties of this approach are derived. The experimental demonstration is performed by quantifying the surface variations induced by the magnetorheological finishing process on laser rods.

Longitudinal Associations Between Interpersonal Relationship Functioning and Mood Episode Severity in Youth with Bipolar Disorder

PubMed Central

Siegel, Rebecca S.; Hoeppner, Bettina; Yen, Shirley; Stout, Robert L; Weinstock, Lauren M.; Hower, Heather M.; Birmaher, Boris; Goldstein, Tina R.; Goldstein, Benjamin I.; Hunt, Jeffrey I.; Strober, Michael; Axelson, David A.; Gill, Mary Kay; Keller, Martin B.

2014-01-01

This study examined the longitudinal association between mood episode severity and relationships in BP youth. Participants were 413 Course and Outcome of Bipolar Youth study youth, aged 12.6 ± 3.3 years. Monthly ratings of relationships (parents, siblings, and friends) and mood episode severity were assessed by the Adolescent Longitudinal Interval Follow-Up Evaluation (ALIFE) Psychosocial Functioning Schedule (PFS) and Psychiatric Rating Scales (PSR) on average every 8.2 months over 5.1 years. Correlations examined whether participants with increased episode severity also reported poorer relationships, and also examined whether fluctuations in episode severity predicted fluctuations in relationships, and vice versa. Results indicated that participants with greater mood episode severity also had worse relationships. Longitudinally, participants had largely stable relationships. To the extent that there were associations, changes in parental relationships may precede changes in episode severity, although the magnitude of this finding was small. Findings have implications for relationship interventions in BP youth. PMID:25668652

Minimization of reflection cracks in flexible pavements.

DOT National Transportation Integrated Search

1977-01-01

This report describes the performance of fabrics used under overlays in an effort to minimize longitudinal and alligator cracking in flexible pavements. It is concluded, although the sample size is small, that the treatments will extend the pavement ...

Advantages and disadvantages : longitudinal vs. repeated cross-section surveys

DOT National Transportation Integrated Search

1979-01-01

Results are described of experiments conducted in Mississippi, California, and Oregon testing the effectiveness of speed control signs in rural school zones and small communities on high-speed, two-lane highways. Signs tested included existing signin...

Correlates of change in student reported parent involvement in schooling: a new look at the National Education Longitudinal Study of 1988.

PubMed

Stone, Susan

2006-10-01

Using a subsample (2174 students, 174 schools) from the National Education Longitudinal Study of 1988 (NELS), this study drew on Eccles and Harold's (1996) framework of parent involvement in schooling to estimate the relative influence of key child, family, and school characteristics on change in three types of student-reported parent involvement in schooling between eighth and tenth grades: home communication about school, monitoring, and direct interactions with schools. It also examines relationships between changes in involvement, change in grade point average (GPA), and dropout. Overall, measured school effects accounted for a small proportion of the variation in changes in home communication and direct parent interactions with schools. Sustained home communication related to higher grades and lower likelihood of dropout, although the size of effects was small. (c) 2007 APA, all rights reserved

Flight Test of the Aerojet 7KS-6000 T-27 Jato Rocket Motor

NASA Technical Reports Server (NTRS)

Bond, Aleck C.; Thibodaux, Joseph G., Jr.

1949-01-01

A flight test of the Aero jet Engineering Corporation's 7KS-6000 T-27 Jato rocket motor was conducted at the Langley Pilotless Aircraft Research Station at Wallops Island, Va, to determine the flight performance characteristics of the motor. The flight test imposed an absolute longitudinal acceleration of 9.8 g upon the rocket motor at 2.8 seconds after launching. The total impulse developed by the motor was 43,400 pound-seconds, and the thrusting time was 7.58 seconds. The maximum thrust was 7200 pounds and occurred at 4.8 seconds after launching. No thrust irregularities attributable to effects of the flight longitudinal acceleration were observed. Certain small thrust irregularities occurred in the flight test which appear to correspond to irregularities observed in static tests conducted elsewhere. A hypothesis regarding the origin of these small irregularities is presented.

Fiber Optic Magnetic Field Sensors Using Metallic Glass Coatings.

NASA Astrophysics Data System (ADS)

Wang, Yu.

1990-01-01

In this thesis we have investigated the use of a magnetostrictive material with a single-mode optical fiber for detecting weak magnetic fields. The amorphous alloy Metglas^circler 2605SC (Fe_{81}B_ {13.5}Si_{3.5} C_2) was chosen as the magnetostrictive material because of the combination of its large magnetostriction and small magnetic anisotropy field among all available metals. For efficient coupling between the magnetostrictive material and the optical fiber, the magnetostrictive material was directly deposited onto the single-mode optical fiber. The coated fibers were used as the sensing element in the fiber optic magnetic field sensor (FOMS). Very high quality thick metallic glass films of the Metglas 2605 SC have been deposited using triode-magneton sputtering. This is the first time such material has been successfully deposited onto an optical fiber or onto any other substrate. The films were also deposited onto glass slides to allow the study of the magnetic properties of the film. The thicknesses of these films were 5-15 mum. The magnetic property of primary interest for our sensor application is the induced longitudinal magnetostrictive strain. However, the other magnetic properties such as magnetic anisotropy, surface and bulk coercivities, magnetic homogeneity and magnetization all affect the magnetostrictive response of the material. We have used ferromagnetic resonance (FMR) at microwave frequencies to study the magnetic anisotropy and homogeneity; vibrating sample magnetometry (VSM) to study the bulk magnetic hysteresis responses and coercivity; and the longitudinal magneto-optic kerr effect (LMOKE) to study the surface magnetic hysteresis responses and coercivity. The isothermalmagnetic annealing effect on these properties has also been studied in detail. The fiber optic magnetic field sensor constructed using the metallic-glass-coated fiber was tested. An electronic feedback control loop using a PZT cylinder was constructed for stabilizing the sensor operation. Magnetic field detection at different dither frequencies was studied in detail. The estimated minimum detectable magnetic field was about 3 times 10^{-7 } Oe. A simplified elastic model was used for the theoretical calculation of the phase shift induced in a metallic-glass -coated optical fiber with a longitudinal applied magnetic field. The phase shift as a function of coating thickness was calculated, and the experimental results at certain thicknesses were compared with the calculation. The frequency response of the FOMS was also studied in some detail. Three different configurations were used for the study of the frequency response. The results indicate that the resonances observed in the FOMS are most likely related to the mechanical resonance of the optical fiber.

Small scale homelike special care units and traditional special care units: effects on cognition in dementia; a longitudinal controlled intervention study.

PubMed

Kok, Jeroen S; van Heuvelen, Marieke J G; Berg, Ina J; Scherder, Erik J A

2016-02-16

Evidence shows that living in small scale homelike Special Care Units (SCU) has positive effects on behavioural and psychological symptoms of patients with dementia. Effects on cognitive functioning in relation to care facilities, however, are scarcely investigated. The purpose of this study is to gain more insight into the effects of living in small scale homelike Special Care Units, compared to regular SCU's, on the course of cognitive functioning in dementia. A group of 67 patients with dementia who moved from a regular SCU to a small scale homelike SCU and a group of 48 patients with dementia who stayed in a regular SCU participated in the study. Cognitive and behavioural functioning was assessed by means of a neuropsychological test battery and observation scales one month before (baseline), as well as 3 (post) and 6 months (follow-up) after relocation. Comparing the post and follow-up measurement with the baseline measurement, no significant differences on separate measures of cognitive functioning between both groups were found. Additional analyses, however, on 'domain clusters' revealed that global cognitive functioning of the small scale homelike SCU group showed significantly less cognitive decline three months after the transfer (p < 0.05). Effect sizes (95% CI) show a tendency for better aspects of cognition in favour of the homelike small scaled SCU group, i.e., visual memory, picture recognition, cognitive decline as observed by representatives and the clustered domains episodic memory and global cognitive functioning. While there is no significant longitudinal effect on the progression of cognitive decline comparing small scaled homelike SCU's with regular SCU's for patients with dementia, analyses on the domain clusters and effect sizes cautiously suggest differences in favour of the small scaled homelike SCU for different aspects of cognition.

77 FR 23229 - Submission for OMB Review; Small Business Innovation Research (SBIR) Program-Phase I-Grant...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-04-18

....133). This is in response to Public Law 106- 554, the ``Small Business Reauthorization Act of [[Page... DEPARTMENT OF EDUCATION Submission for OMB Review; Small Business Innovation Research (SBIR) Program--Phase I--Grant Application Package SUMMARY: This application package invites small business...

Coping and Adaptation in Adolescence.

ERIC Educational Resources Information Center

Newman, Barbara N.

1979-01-01

Describes the results of four longitudinal studies of adolescent development that focus on coping styles, maturity of defenses, adaptation to school environments, and predictors of educational and occupational attainment. Implications are discussed in terms of linking adolescence with other phases of development. (Author/SS)

Phase II Study Proposal Briefs.

ERIC Educational Resources Information Center

National Center for the Study of Postsecondary Educational Supports, Honolulu, HI.

This document collects 23 study proposal briefs presented to the National Center for the Study of Postsecondary Educational Supports. The proposals address the following topics concerned with postsecondary services for students with disabilities: cultural empowerment, longitudinal analysis of postsecondary students' experience, effective models of…

Longitudinal structure of stationary planetary waves in the middle atmosphere - extraordinary years

NASA Astrophysics Data System (ADS)

Lastovicka, Jan; Krizan, Peter; Kozubek, Michal

2018-01-01

One important but little studied factor in the middle atmosphere meridional circulation is its longitudinal structure. Kozubek et al. (2015) disclosed the existence of the two-cell longitudinal structure in meridional wind at 10 hPa at higher latitudes in January. This two-cell structure is a consequence of the stratospheric stationary wave SPW1 in geopotential heights. Therefore here the longitudinal structure in geopotential heights and meridional wind is analysed based on MERRA data over 1979-2013 and limited NOGAPS-ALPHA data in order to find its persistence and altitudinal dependence with focus on extraordinary years. The SPW1 in geopotential heights and related two-cell structure in meridional wind covers the middle stratosphere (lower boundary ˜ 50 hPa), upper stratosphere and most of the mesosphere (almost up to about 0.01 hPa). The two-cell longitudinal structure in meridional wind is a relatively persistent feature; only 9 out of 35 winters (Januaries) display more complex structure. Morphologically the deviation of these extraordinary Januaries consists in upward propagation of the second (Euro-Atlantic) peak (i.e. SPW2 structure) to higher altitudes than usually, mostly up to the mesosphere. All these Januaries occurred under the positive phase of PNA (Pacific North American) index but there are also other Januaries under its positive phase, which behave in an ordinary way. The decisive role in the existence of extraordinary years (Januaries) appears to be played by the SPW filtering by the zonal wind pattern. In all ordinary years the mean zonal wind pattern in January allows the upward propagation of SPW1 (Aleutian peak in geopotential heights) up to the mesosphere but it does not allow the upward propagation of the Euro-Atlantic SPW2 peak to and above the 10 hPa level. On the other hand, the mean zonal wind filtering pattern in extraordinary Januaries is consistent with the observed pattern of geopotential heights at higher altitudes.

Changes in social isolation and loneliness following total hip and knee arthroplasty: longitudinal analysis of the English Longitudinal Study of Ageing (ELSA) cohort.

PubMed

Smith, T O; Dainty, J R; MacGregor, A J

2017-09-01

To determine the prevalence and change in social isolation and loneliness in people before and after total hip arthroplasty (THA) and total knee arthroplasty (TKA) in England. The English Longitudinal Study of Ageing (ELSA) dataset, a prospective study of community-dwelling older adults, was used to identify people who had undergone primary THA or TKA because of osteoarthritis. Social isolation was assessed using the ELSA Social Isolation Index. Loneliness was evaluated using the Revised University of California, Los Angeles (UCLA) Loneliness Scale. The prevalence of social isolation and loneliness were calculated and multilevel modelling was performed to assess the potential change of these measures before arthroplasty, within a two-year operative-recovery phase and a following two-year follow-up. The sample consisted of 393 people following THA and TKA. The prevalence of social isolation and loneliness changed from 16.9% to 18.8% pre-operative to 21.8% and 18.9% at the final post-operative follow-up respectively. This was not a statistically significant change for either measure (P = 0.15; P = 0.74). There was a significant difference in social isolation at the recovery phase compared to the pre-operative phase (P = 0.01), where people following arthroplasty reported an increase in social isolation (16.9-21.4%). There was no significant difference between the assessment phases in respect to UCLA Loneliness Scale score (P ≥ 0.74). Given the negative physical and psychological consequences which social isolation and loneliness can have on individuals following THA or TKA, clinicians should be mindful of this health challenge for this population. The reported prevalence of social isolation and loneliness suggests this is an important issue. Copyright © 2017 Osteoarthritis Research Society International. Published by Elsevier Ltd. All rights reserved.

Effectiveness of a redesigned water diversion using rock vortex weirs to enhance longitudinal connectivity for small Salmonids

USGS Publications Warehouse

Martens, Kyle D.; Connolly, Patrick J.

2010-01-01

For nearly 100 years, water diversions have affected fish passage in Beaver Creek, a tributary of the lower Methow River in north-central Washington State. From 2000 to 2004, four dam-style water diversions were replaced with a series of rock vortex weirs (RVWs). The weirs were designed to allow fish passage while maintaining the ability to divert water into irrigation canals. We observed the new appearance of three species (juvenile Chinook salmon Oncorhynchus tshawytscha, juvenile coho salmon O. kisutch, and mountain whitefish Prosopium williamsoni) upstream of the RVWs, indicating successful restoration of longitudinal connectivity. We used passive integrated transponder (PIT) tags and instream PIT tag interrogation systems during 2004–2007 to evaluate upstream passage of small salmonids (<240 mm fork length) through one series of RVWs. We documented 109 upstream passage events by small salmonids through the series of RVWs; most of the events (81%) involved passage of rainbow trout O. mykiss or juvenile steelhead (anadromous rainbow trout). Small rainbow trout or steelhead ranging from 86 to 238 mm (adjusted fork length) were able to pass upstream through the RVWs, although a delay in fish passage at discharges below 0.32 m3/s was detected in comparison with nearby control sections.

Regularly incremented phase encoding - MR fingerprinting (RIPE-MRF) for enhanced motion artifact suppression in preclinical cartesian MR fingerprinting.

PubMed

Anderson, Christian E; Wang, Charlie Y; Gu, Yuning; Darrah, Rebecca; Griswold, Mark A; Yu, Xin; Flask, Chris A

2018-04-01

The regularly incremented phase encoding-magnetic resonance fingerprinting (RIPE-MRF) method is introduced to limit the sensitivity of preclinical MRF assessments to pulsatile and respiratory motion artifacts. As compared to previously reported standard Cartesian-MRF methods (SC-MRF), the proposed RIPE-MRF method uses a modified Cartesian trajectory that varies the acquired phase-encoding line within each dynamic MRF dataset. Phantoms and mice were scanned without gating or triggering on a 7T preclinical MRI scanner using the RIPE-MRF and SC-MRF methods. In vitro phantom longitudinal relaxation time (T 1 ) and transverse relaxation time (T 2 ) measurements, as well as in vivo liver assessments of artifact-to-noise ratio (ANR) and MRF-based T 1 and T 2 mean and standard deviation, were compared between the two methods (n = 5). RIPE-MRF showed significant ANR reductions in regions of pulsatility (P < 0.005) and respiratory motion (P < 0.0005). RIPE-MRF also exhibited improved precision in T 1 and T 2 measurements in comparison to the SC-MRF method (P <  0.05). The RIPE-MRF and SC-MRF methods displayed similar mean T 1 and T 2 estimates (difference in mean values < 10%). These results show that the RIPE-MRF method can provide effective motion artifact suppression with minimal impact on T 1 and T 2 accuracy for in vivo small animal MRI studies. Magn Reson Med 79:2176-2182, 2018. © 2017 International Society for Magnetic Resonance in Medicine. © 2017 International Society for Magnetic Resonance in Medicine.

Longitudinal posturography and rotational testing in children 3-9 years of age: Normative data

PubMed Central

Casselbrant, Margaretha L.; Mandel, Ellen M.; Sparto, Patrick J; Perera, Subashan; Redfern, Mark S.; Fall, Patricia A.; Furman, Joseph M.

2010-01-01

Objective To obtain normative longitudinal vestibulo-ocular and balance test data in children from ages 3 to 9 with normal middle-ear status. Study Design Prospective, longitudinal cohort Setting Tertiary care pediatric hospital Subjects and Methods Three-year-old children were entered and tested yearly. Subjects underwent earth vertical axis rotation testing using sinusoidal and constant velocity stimuli and performed the Sensory Organization Test. Results One hundred forty-eight children were entered and usable data were collected on 127 children. A linear increase in the vestibulo-ocular reflex gain as children aged was found, without a change in the phase of the response. An age-related linear increase in Equilibrium Scores, indicating reduced postural sway, was also observed. Conclusion These normative data can be used in the evaluation of dizziness and balance disorders in children. PMID:20416461

Design of a Subscale Propellant Slag Evaluation Motor Using Two-Phase Fluid Dynamic Analysis

NASA Technical Reports Server (NTRS)

Whitesides, R. Harold; Dill, Richard A.; Purinton, David C.; Sambamurthi, Jay K.

1996-01-01

Small pressure perturbations in the Space Shuttle Reusable Solid Rocket Motor (RSRM) are caused by the periodic expulsion of molten aluminum oxide slag from a pool that collects in the aft end of the motor around the submerged nozzle nose during the last half of motor operation. It is suspected that some motors produce more slag than others due to differences in aluminum oxide agglomerate particle sizes that may relate to subtle differences in propellant ingredient characteristics such as particle size distributions or processing variations. A subscale motor experiment was designed to determine the effect of propellant ingredient characteristics on the propensity for slag production. An existing 5 inch ballistic test motor was selected as the basic test vehicle. The standard converging/diverging nozzle was replaced with a submerged nose nozzle design to provide a positive trap for the slag that would increase the measured slag weights. Two-phase fluid dynamic analyses were performed to develop a nozzle nose design that maintained similitude in major flow field features with the full scale RSRM. The 5 inch motor was spun about its longitudinal axis to further enhance slag collection and retention. Two-phase flow analysis was used to select an appropriate spin rate along with other considerations, such as avoiding bum rate increases due to radial acceleration effects. Aluminum oxide particle distributions used in the flow analyses were measured in a quench bomb for RSRM type propellants with minor variations in ingredient characteristics. Detailed predictions for slag accumulation weights during motor bum compared favorably with slag weight data taken from defined zones in the subscale motor and nozzle. The use of two-phase flow analysis proved successful in gauging the viability of the experimental program during the planning phase and in guiding the design of the critical submerged nose nozzle.

Phase modulation of the bucket stops bunch oscillations at the Fermilab Tevatron

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tan, C.Y.; Burov, A.; /Fermilab

2012-04-02

Bunches in the Tevatron are known to exhibit longitudinal oscillations which persist indefinitely. These oscillations are colloquially called 'dancing bunches.' Although the dancing proton bunches do not cause single bunch emittance growth or beam loss at injection, they lead to bunch lengthening at collisions. In Tevatron operations, a longitudinal damper has been built which stops this dance and damps out coupled bunch modes. Recent theoretical work predicts that the dance can also be stopped by an appropriate change in the bunch distribution. This paper describes the Tevatron experiments which support this theory.

Electro-opto-mechanical radio-frequency oscillator driven by guided acoustic waves in standard single-mode fiber

NASA Astrophysics Data System (ADS)

London, Yosef; Diamandi, Hilel Hagai; Zadok, Avi

2017-04-01

An opto-electronic radio-frequency oscillator that is based on forward scattering by the guided acoustic modes of a standard single-mode optical fiber is proposed and demonstrated. An optical pump wave is used to stimulate narrowband, resonant guided acoustic modes, which introduce phase modulation to a co-propagating optical probe wave. The phase modulation is converted to an intensity signal at the output of a Sagnac interferometer loop. The intensity waveform is detected, amplified, and driven back to modulate the optical pump. Oscillations are achieved at a frequency of 319 MHz, which matches the resonance of the acoustic mode that provides the largest phase modulation of the probe wave. Oscillations at the frequencies of competing acoustic modes are suppressed by at least 40 dB. The linewidth of the acoustic resonance is sufficiently narrow to provide oscillations at a single longitudinal mode of the hybrid cavity. Competing longitudinal modes are suppressed by at least 38 dB as well. Unlike other opto-electronic oscillators, no radio-frequency filtering is required within the hybrid cavity. The frequency of oscillations is entirely determined by the fiber opto-mechanics.

The distribution of conformational disorder in the high-temperature phases of the crystalline n-alkanes

NASA Astrophysics Data System (ADS)

Maroncelli, M.; Strauss, H. L.; Snyder, R. G.

1985-03-01

The distributions of conformational defects that exist in the high-temperature phase II (also referred to as the hexagonal or rotator phase) of the crystalline n-alkanes C21 and C29 have been measured by an infrared CD2-substitution technique and have been accounted for in terms of a lattice model that provides freedom for longitudinal displacement of the chains. The defects consist almost entirely of gtg' kinks distributed nonuniformly along the chain. The uneven distribution is indicated in the variation in the concentration of gauche bonds measured at various sites along the chain. The highest concentration is at the chain ends, and the concentrations at interior sites decrease exponentially in going toward the middle. To explain the distribution we used a modification of a lattice model that had been successfully applied to the lipid bilayer. Comparison of observed distributions with those computed from the model indicates that the factors that determine the shape of the distribution are quite different in the n-alkane and bilayer cases. For the bilayer, the dominant factor is the variation in the lateral density of chains; for the n-alkane, the dominant factor is associated with longitudinal displacement of the chains.

Nudging at the checkout counter - A longitudinal study of the effect of a food repositioning nudge on healthy food choice.

PubMed

Van Gestel, L C; Kroese, F M; De Ridder, D T D

2018-06-01

Objective The current study is a longitudinal conceptual replication and aimed to investigate the effect of a food repositioning nudge on healthy food choice in a kiosk. Design During eight weeks, sales data were collected. The former four weeks formed the baseline phase and the latter four weeks formed the nudge phase where healthy food products were repositioned at the checkout counter display, while unhealthy alternatives remained available elsewhere in the store. Main Outcome Measures The main variable of interest was the proportion of healthy food products (selected to be repositioned) sold per day. Also exit interviews were administered to gather individual level data about purchases, and awareness and opinions of the nudge. Results Results showed that the proportion of selected healthy food products in total food sales was higher in all four nudge weeks than in all four baseline weeks. Individual level data showed that more customers had bought a selected healthy food product in the nudge phase and that customers generally approved of the nudge. Conclusion The current study strengthened the empirical evidence base of repositioning healthy food products as an effective and well-accepted nudge.

Electrons, phonons and superconductivity in rocksalt and tungsten-carbide phases of CrC.

PubMed

Tütüncü, H M; Baǧcı, S; Srivastava, G P; Akbulut, A

2012-11-14

We present results of ab initio theoretical investigations of the electronic structure, phonon dispersion relations, electron-phonon interaction and superconductivity in the rocksalt and tungsten-carbide phases of CrC. It is found that, compared to the stable tungsten-carbide phase, the metastable rocksalt phase is characterized by a much larger electronic density of states at the Fermi level. The phonon spectra of the rocksalt phase exhibit anomalies in the dispersion curves of both the transverse and longitudinal acoustic branches along the main symmetry directions. A combination of these characteristic electronic and phonon properties leads to an order of magnitude larger value of the electron-phonon coupling constant (λ = 2.66) for the rocksalt phase compared to that for the tungsten-carbide phase (λ = 0.24). Our calculations suggest that superconducting transition temperature values of 0.01 K and 25-35 K may be expected for the tungsten-carbide and rocksalt phases, respectively.

Estimating correlation between multivariate longitudinal data in the presence of heterogeneity.

PubMed

Gao, Feng; Philip Miller, J; Xiong, Chengjie; Luo, Jingqin; Beiser, Julia A; Chen, Ling; Gordon, Mae O

2017-08-17

Estimating correlation coefficients among outcomes is one of the most important analytical tasks in epidemiological and clinical research. Availability of multivariate longitudinal data presents a unique opportunity to assess joint evolution of outcomes over time. Bivariate linear mixed model (BLMM) provides a versatile tool with regard to assessing correlation. However, BLMMs often assume that all individuals are drawn from a single homogenous population where the individual trajectories are distributed smoothly around population average. Using longitudinal mean deviation (MD) and visual acuity (VA) from the Ocular Hypertension Treatment Study (OHTS), we demonstrated strategies to better understand the correlation between multivariate longitudinal data in the presence of potential heterogeneity. Conditional correlation (i.e., marginal correlation given random effects) was calculated to describe how the association between longitudinal outcomes evolved over time within specific subpopulation. The impact of heterogeneity on correlation was also assessed by simulated data. There was a significant positive correlation in both random intercepts (ρ = 0.278, 95% CI: 0.121-0.420) and random slopes (ρ = 0.579, 95% CI: 0.349-0.810) between longitudinal MD and VA, and the strength of correlation constantly increased over time. However, conditional correlation and simulation studies revealed that the correlation was induced primarily by participants with rapid deteriorating MD who only accounted for a small fraction of total samples. Conditional correlation given random effects provides a robust estimate to describe the correlation between multivariate longitudinal data in the presence of unobserved heterogeneity (NCT00000125).

A poroelastic medium saturated by a two-phase capillary fluid

NASA Astrophysics Data System (ADS)

Shelukhin, V. V.

2014-09-01

By Landau's approach developed for description of superfluidity of 2He, we derive a mathematical model for a poroelastic medium saturated with a two-phase capillary fluid. The model describes a three-velocity continuum with conservation laws which obey the basic principles of thermodynamics and which are consistent with the Galilean transformations. In contrast to Biot' linear theory, the equations derived allow for finite deformations. As the acoustic analysis reveals, there is one more longitudinal wave in comparison with the poroelastic medium saturated with a one-phase fluid. We prove that such a result is due to surface tension.

Liquid sodium testing of in-house phased array EMAT transducer for L-wave applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Le Bourdais, F.; Le Polles, T.; Baque, F.

2015-07-01

This paper describes the development of an in-house phased array EMAT transducer for longitudinal wave inspection in liquid sodium. The work presented herein is part of an undergoing project aimed at improving in-service inspection techniques for the ASTRID reactor project. The design process of the phased array EMAT probe is briefly explained and followed by a review of experimental test results. We first present test results obtained in the laboratory while the last part of the paper describes the liquid sodium testing and the produced ultrasound images. (authors)

77 FR 23228 - Notice of Submission for OMB Review; Small Business Innovation Research (SBIR) Program-Phase II...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-04-18

... business concerns to submit a Phase II application for the Small Business Innovation Research (SBIR) Program (CFDA 84.133). This is in response to Public Law 106-554, the ``Small Business Reauthorization Act... DEPARTMENT OF EDUCATION Notice of Submission for OMB Review; Small Business Innovation Research...

Does the local food environment around schools affect diet? Longitudinal associations in adolescents attending secondary schools in East London

PubMed Central

2013-01-01

Background The local retail food environment around schools may act as a potential risk factor for adolescent diet. However, international research utilising cross-sectional designs to investigate associations between retail food outlet proximity to schools and diet provides equivocal support for an effect. In this study we employ longitudinal perspectives in order to answer the following two questions. First, how has the local retail food environment around secondary schools changed over time and second, is this change associated with change in diet of students at these schools? Methods The locations of retail food outlets and schools in 2001 and 2005 were geo-coded in three London boroughs. Network analysis in a Geographic Information System (GIS) ascertained the number, minimum and median distances to food outlets within 400 m and 800 m of the school location. Outcome measures were ‘healthy’ and ‘unhealthy’ diet scores derived from adolescent self-reported data in the Research with East London Adolescents: Community Health Survey (RELACHS). Adjusted associations between distance from school to food retail outlets, counts of outlets near schools and diet scores were assessed using longitudinal (2001–2005 n=757) approaches. Results Between 2001 and 2005 the number of takeaways and grocers/convenience stores within 400 m of schools increased, with many more grocers reported within 800 m of schools in 2005 (p< 0.001). Longitudinal analyses showed a decrease of the mean healthy (−1.12, se 0.12) and unhealthy (−0.48, se 0.16) diet scores. There were significant positive relationships between the distances travelled to grocers and healthy diet scores though effects were very small (0.003, 95%CI 0.001 – 0.006). Significant negative relationships between proximity to takeaways and unhealthy diet scores also resulted in small parameter estimates. Conclusions The results provide some evidence that the local food environment around secondary schools may influence adolescent diet, though effects were small. Further research on adolescents’ food purchasing habits with larger samples in varied geographic regions is required to identify robust relationships between proximity and diet, as small numbers, because of confounding, may dilute effect food environment effects. Data on individual foods purchased in all shop formats may clarify the frequent, overly simple classification of grocers as ‘healthy’. PMID:23347757

Common mode frequency instability in internally phase-locked terahertz quantum cascade lasers.

PubMed

Wanke, M C; Grine, A D; Fuller, C T; Nordquist, C D; Cich, M J; Reno, J L; Lee, Mark

2011-11-21

Feedback from a diode mixer integrated into a 2.8 THz quantum cascade laser (QCL) was used to phase lock the difference frequencies (DFs) among the Fabry-Perot (F-P) longitudinal modes of a QCL. Approximately 40% of the DF power was phase locked, consistent with feedback loop bandwidth of 10 kHz and phase noise bandwidth ~0.5 MHz. While the locked DF signal has ≤ 1 Hz linewidth and negligible drift over ~30 min, mixing measurements between two QCLs and between a QCL and molecular gas laser show that the common mode frequency stability is no better than a free-running QCL. © 2011 Optical Society of America

A Study of English Language Training for Refugees in the United States. Phase Three: The Influence of Language Training and Employment on Adult Refugees' Acquisition of English. Technical Report.

ERIC Educational Resources Information Center

Arter, Judith; And Others

The third phase of a national study of the impact of English language training programs on adult Southeast Asian refugees in the United States involved a longitudinal study of 400 recently-arrived refugees chosen at random from reception lines of refugee centers in four metropolitan areas: Portland, Oregon; San Diego; Oklahoma City; and Denver.…

Evolution of the structure and the phase composition of a bainitic structural steel during plastic deformation

NASA Astrophysics Data System (ADS)

Nikitina, E. N.; Glezer, A. M.; Ivanov, Yu. F.; Aksenova, K. V.; Gromov, V. E.; Kazimirov, S. A.

2017-10-01

The evolution of the phase composition and the imperfect substructure of the 30Kh2N2MFA bainitic structural steel subjected to compressive deformation by 36% is quantitatively analyzed. It is shown that deformation is accompanied by an increase in the scalar dislocation density, a decrease in the longitudinal fragment sizes, an increase in the number of stress concentrators, the dissolution of cementite particles, and the transformation of retained austenite.

Beginning Awareness-Rigidity-Flexibility: A Longitudinal Analysis of Sex-Role Stereotyping in 4- to 10-Year-Old Children (Langsschnittliche Analyse von Entwicklungsmerkmalen der Geschlechtstypisierung im Kindersalter. Arbeiten aud dem Forschungsprojekt Nr. 5. 1989/1).

ERIC Educational Resources Information Center

Trautner, Hanns Martin; And Others

A three-phase developmental model of sex-role stereotyping that viewed the acquisition of sex-role stereotypes as part of the broader process of the development of social understanding was proposed. Phases in the model included: (1) beginning awareness of sex-role differentiation; (2) rigid sex-role stereotyping; and (3) flexible sex-role…

An analytical theory of a scattering of radio waves on meteoric ionization - II. Solution of the integro-differential equation in case of backscatter

NASA Astrophysics Data System (ADS)

Pecina, P.

2016-12-01

The integro-differential equation for the polarization vector P inside the meteor trail, representing the analytical solution of the set of Maxwell equations, is solved for the case of backscattering of radio waves on meteoric ionization. The transversal and longitudinal dimensions of a typical meteor trail are small in comparison to the distances to both transmitter and receiver and so the phase factor appearing in the kernel of the integral equation is large and rapidly changing. This allows us to use the method of stationary phase to obtain an approximate solution of the integral equation for the scattered field and for the corresponding generalized radar equation. The final solution is obtained by expanding it into the complete set of Bessel functions, which results in solving a system of linear algebraic equations for the coefficients of the expansion. The time behaviour of the meteor echoes is then obtained using the generalized radar equation. Examples are given for values of the electron density spanning a range from underdense meteor echoes to overdense meteor echoes. We show that the time behaviour of overdense meteor echoes using this method is very different from the one obtained using purely numerical solutions of the Maxwell equations. Our results are in much better agreement with the observations performed e.g. by the Ondřejov radar.

All solid-state diode pumped Nd:YAG MOPA with stimulated Brillouin phase conjugate mirror

NASA Astrophysics Data System (ADS)

Offerhaus, H. L.; Godfried, H. P.; Witteman, W. J.

1996-02-01

At the Nederlands Centrum voor Laser Research (NCLR) a 1 kHz diode-pumped Nd:YAG Master Oscillator Power Amplifier (MOPA) chain with a Stimulated Brillouin Scattering (SBS) Phase Conjugate mirror is designed and operated. A small Brewster angle Nd:YAG slab (2 by 2 by 20 mm) is side pumped with 200 μs diode pulses in a stable oscillator. The oscillator is Q-switched and injection seeded with a commercial diode pumped single frequency CW Nd:YAG laser. The output consists of single-transverse, single-longitudinal mode 25 ns FWHM-pulses at 1064 nm. The oscillator slab is imaged on a square aperture that transmits between 3 and 2 mJ (at 100 and 400 Hz, resp.) The aperture is subsequently imaged four times in the amplifier. The amplifier is a 3 by 6 by 60 mm Brewster angle zig-zag slab, pumped by an 80-bar diode stack with pulses up to 250 μs. After the second pass the light is focused in two consecutive cells containing Freon-113 for wave-front reversal in an oscillator/amplifier-setup with a reflectivity of 60%. The light then passes through the amplifier twice more to produce 20 W (at 400 Hz) of output with near diffraction limited beam quality. To increase the output to 50 W at 1 kHz thermal lensing in the oscillator will be reduced.

Suppression of phase mixing in drift-kinetic plasma turbulence

DOE Office of Scientific and Technical Information (OSTI.GOV)

Parker, J. T., E-mail: joseph.parker@stfc.ac.uk; OCIAM, Mathematical Institute, University of Oxford, Andrew Wiles Building, Radcliffe Observatory Quarter, Woodstock Road, Oxford OX2 6GG; Brasenose College, Radcliffe Square, Oxford OX1 4AJ

2016-07-15

Transfer of free energy from large to small velocity-space scales by phase mixing leads to Landau damping in a linear plasma. In a turbulent drift-kinetic plasma, this transfer is statistically nearly canceled by an inverse transfer from small to large velocity-space scales due to “anti-phase-mixing” modes excited by a stochastic form of plasma echo. Fluid moments (density, velocity, and temperature) are thus approximately energetically isolated from the higher moments of the distribution function, so phase mixing is ineffective as a dissipation mechanism when the plasma collisionality is small.

An Evidence-based, Longitudinal Curriculum for Resident Physician Wellness: The 2017 Resident Wellness Consensus Summit

PubMed Central

Arnold, Jacob; Tango, Jennifer; Walker, Ian; Waranch, Chris; McKamie, Joshua; Poonja, Zafrina

2018-01-01

Introduction Physicians are at much higher risk for burnout, depression, and suicide than their non-medical peers. One of the working groups from the May 2017 Resident Wellness Consensus Summit (RWCS) addressed this issue through the development of a longitudinal residency curriculum to address resident wellness and burnout. Methods A 30-person (27 residents, three attending physicians) Wellness Curriculum Development workgroup developed the curriculum in two phases. In the first phase, the workgroup worked asynchronously in the Wellness Think Tank – an online resident community – conducting a literature review to identify 10 core topics. In the second phase, the workgroup expanded to include residents outside the Wellness Think Tank at the live RWCS event to identify gaps in the curriculum. This resulted in an additional seven core topics. Results Seventeen foundational topics served as the framework for the longitudinal resident wellness curriculum. The curriculum includes a two-module introduction to wellness; a seven-module “Self-Care Series” focusing on the appropriate structure of wellness activities and everyday necessities that promote physician wellness; a two-module section on physician suicide and self-help; a four-module “Clinical Care Series” focusing on delivering bad news, navigating difficult patient encounters, dealing with difficult consultants and staff members, and debriefing traumatic events in the emergency department; wellness in the workplace; and dealing with medical errors and shame. Conclusion The resident wellness curriculum, derived from an evidence-based approach and input of residents from the Wellness Think Tank and the RWCS event, provides a guiding framework for residency programs in emergency medicine and potentially other specialties to improve physician wellness and promote a culture of wellness. PMID:29560063

Single-longitudinal mode distributed-feedback fiber laser with low-threshold and high-efficiency

NASA Astrophysics Data System (ADS)

Jiang, Man; Zhou, Pu; Gu, Xijia

2018-01-01

Single-frequency fiber laser has attracted a lot of interest in recent years due to its numerous application potentials in telecommunications, LIDAR, high resolution sensing, atom frequency standard, etc. Phosphate glass fiber is one of the candidates for building compact high gain fiber lasers because of its capability of high-concentration of rare-earth ions doping in fiber core. Nevertheless, it is challenging for the integration of UV-written intra-core fiber Bragg gratings into the fiber laser cavity due to the low photosensitivity of phosphate glass fiber. The research presented in this paper will focus on demonstration of UV-written Bragg gratings in phosphate glass fiber and its application in direct-written short monolithic single-frequency fiber lasers. Strong π-phase shift Bragg grating structure is direct-inscribed into the Er/Yb co-doped gain fiber using an excimer laser, and a 5-cm-long phase mask is used to inscribe a laser cavity into the Er/Yb co-doped phosphate glass fibers. The phase mask is a uniform mask with a 50 μm gap in the middle. The fiber laser device emits output power of 10.44 mW with a slope efficiency of 21.5% and the threshold power is about 42.8 mW. Single-longitudinal mode operation is validated by radio frequency spectrum measurement. Moreover, the output spectrum at the highest power shows an excellent optical signal to noise ratio of about 70 dB. These results, to the best of our knowledge, show the lowest power threshold and highest efficiency among the reports that using the same structure to achieve single-longitudinal mode laser output.

An Evidence-based, Longitudinal Curriculum for Resident Physician Wellness: The 2017 Resident Wellness Consensus Summit.

PubMed

Arnold, Jacob; Tango, Jennifer; Walker, Ian; Waranch, Chris; McKamie, Joshua; Poonja, Zafrina; Messman, Anne

2018-03-01

Physicians are at much higher risk for burnout, depression, and suicide than their non-medical peers. One of the working groups from the May 2017 Resident Wellness Consensus Summit (RWCS) addressed this issue through the development of a longitudinal residency curriculum to address resident wellness and burnout. A 30-person (27 residents, three attending physicians) Wellness Curriculum Development workgroup developed the curriculum in two phases. In the first phase, the workgroup worked asynchronously in the Wellness Think Tank - an online resident community - conducting a literature review to identify 10 core topics. In the second phase, the workgroup expanded to include residents outside the Wellness Think Tank at the live RWCS event to identify gaps in the curriculum. This resulted in an additional seven core topics. Seventeen foundational topics served as the framework for the longitudinal resident wellness curriculum. The curriculum includes a two-module introduction to wellness; a seven-module "Self-Care Series" focusing on the appropriate structure of wellness activities and everyday necessities that promote physician wellness; a two-module section on physician suicide and self-help; a four-module "Clinical Care Series" focusing on delivering bad news, navigating difficult patient encounters, dealing with difficult consultants and staff members, and debriefing traumatic events in the emergency department; wellness in the workplace; and dealing with medical errors and shame. The resident wellness curriculum, derived from an evidence-based approach and input of residents from the Wellness Think Tank and the RWCS event, provides a guiding framework for residency programs in emergency medicine and potentially other specialties to improve physician wellness and promote a culture of wellness.

Systematically Asymmetric Heliospheric Magnetic Field: Evidence for a Quadrupole Mode and Non-Axisymmetry with Polarity Flip-Flops

NASA Astrophysics Data System (ADS)

Mursula, K.; Hiltula, T.

2004-10-01

Recent studies of the heliospheric magnetic field (HMF) have detected interesting, systematic hemispherical and longitudinal asymmetries which have a profound significance for the understanding of solar magnetic fields. The in situ HMF measurements since the 1960s show that the heliospheric current sheet (HCS) is systematically shifted (coned) southward during solar minimum times, leading to the concept of a bashful ballerina. While temporary shifts can be considerably larger, the average HCS shift (coning) angle is a few degrees, less than the 7.2∘ tilt of the solar rotation axis. Recent solar observations during the last two solar cycles verify these results and show that the magnetic areas in the northern solar hemisphere are larger and their intensity weaker than in the south during long intervals in the late declining to minimum phase. The multipole expansion reveals a strong quadrupole term which is oppositely directed to the dipole term. These results imply that the Sun has a symmetric quadrupole S0 dynamo mode that oscillates in phase with the dominant dipole A0 mode. Moreover, the heliospheric magnetic field has a strong tendency to produce solar tilts that are roughly opposite in longitudinal phase. This implies is a systematic longitudinal asymmetry and leads to a “flip-flop” type behaviour in the dominant HMF sector whose period is about 3.2 years. This agrees very well with the similar flip-flop period found recently in sunspots, as well as with the observed ratio of three between the activity cycle period and the flip-flop period of sun-like stars. Accordingly, these results require that the solar dynamo includes three modes, A0, S0 and a non-axisymmetric mode. Obviously, these results have a great impact on solar modelling.

Integration of Cognitive Skills as a Cross-Cutting Theme Into the Undergraduate Medical Curriculum at Tehran University of Medical Sciences.

PubMed

Soltani, Akbar; Allaa, Maryam; Moosapour, Hamideh; Aletaha, Azadeh; Shahrtash, Farzaneh; Monajemi, Alireza; Arastoo, Tohid; Ahmadinejad, Maryam; Mirzazadeh, Azim; Khabaz Mafinejad, Mahboobeh

2017-01-01

Nowadays, improvement of thinking skills of students is one of the universally supported aims in the majority of medical schools. This study aims to design longitudinal theme of reasoning, problem-solving and decision-making into the undergraduate medical curriculum at Tehran University of Medical Sciences (TUMS). A participatory approach was applied to design the curriculum during 2009-2011. The project was conducted by the contribution of representatives of both basic and clinical faculty members, students and graduates at Tehran University of Medical Sciences. The first step toward integrating cognitive skills into the curriculum was to assemble a taskforce of different faculty and students, including a wide variety of fields with multidisciplinary expertise using nonprobability sampling and the snowball method. Several meetings with the contribution of experts and some medical students were held to generate the draft of expected outcomes. Subsequently, the taskforce also determined what content would fit best into each phase of the program and what teaching and assessment methods would be more appropriate for each outcome. After a pilot curriculum with a small group of second-year medical students, we implemented this program for all first-year students since 2011 at TUMS. Based on findings, the teaching of four areas, including scientific and critical thinking skills (Basic sciences), problem-solving and reasoning (Pathophysiology), evidence-based medicine (Clerkship), and clinical decision-making (Internship) were considered in the form of a longitudinal theme. The results of this study could be utilized as a useful pattern for integration of psycho-social subjects into the medical curriculum.

Proteolytic inactivation of substance P and neurokinin A in the longitudinal muscle layer of guinea pig small intestine.

PubMed

Nau, R; Schäfer, G; Deacon, C F; Cole, T; Agoston, D V; Conlon, J M

1986-09-01

Membrane vesicles, showing a 21 +/- 2-fold enrichment in the activity of 5'-nucleotidase and a 11 +/- 4-fold enrichment in the activity of angiotensin-converting enzyme relative to homogenate, were prepared from the myenteric plexus-containing longitudinal muscle layer of guinea pig ileum. Incubation of the vesicles with substance P and neurokinin A led to degradation of the peptides, and metabolites were isolated by reverse-phase HPLC and identified by amino acid composition. Cleavages of substance P between Glu6-Phe7, Phe7-Phe8, and Gly9-Leu10 and of neurokinin A between Gly8-Leu9 were observed and could be inhibited in a dose-dependent manner by phosphoramidon, an inhibitor of neutral endopeptidase 24.11. Formation of these metabolites was not completely inhibited by this agent, indicating that a phosphoramidon-insensitive form of endopeptidase 24.11 was present in the gut. Substance P was resistant to degradation by aminopeptidases, but neurokinin A was a substrate for bestatin-sensitive aminopeptidase(s), so that the neurokinin A (3-10) fragment represented the predominant metabolite in the chromatograms. The rate of formation of all the metabolites was not inhibited by enalapril and not enhanced by an increased Cl- concentration, indicating that angiotensin-converting enzyme was unimportant in the degradation process. Degradation of neurokinin A by the vesicles (Km 30 microM; Vmax 7.2 +/- 0.8 nmol min-1 mg of protein-1) was more rapid than degradation of substance P (Km 25 microM; Vmax 4.4 +/- 0.4 nmol min-1 mg of protein-1).

Two passive mechanical conditions modulate power generation by the outer hair cells

PubMed Central

Gracewski, Sheryl M.

2017-01-01

In the mammalian cochlea, small vibrations of the sensory epithelium are amplified due to active electro-mechanical feedback of the outer hair cells. The level of amplification is greater in the base than in the apex of the cochlea. Theoretical studies have used longitudinally varying active feedback properties to reproduce the location-dependent amplification. The active feedback force has been considered to be proportional to the basilar membrane displacement or velocity. An underlying assumption was that organ of Corti mechanics are governed by rigid body kinematics. However, recent progress in vibration measurement techniques reveals that organ of Corti mechanics are too complicated to be fully represented with rigid body kinematics. In this study, two components of the active feedback are considered explicitly—organ of Corti mechanics, and outer hair cell electro-mechanics. Physiological properties for the outer hair cells were incorporated, such as the active force gain, mechano-transduction properties, and membrane RC time constant. Instead of a kinematical model, a fully deformable 3D finite element model was used. We show that the organ of Corti mechanics dictate the longitudinal trend of cochlear amplification. Specifically, our results suggest that two mechanical conditions are responsible for location-dependent cochlear amplification. First, the phase of the outer hair cell’s somatic force with respect to its elongation rate varies along the cochlear length. Second, the local stiffness of the organ of Corti complex felt by individual outer hair cells varies along the cochlear length. We describe how these two mechanical conditions result in greater amplification toward the base of the cochlea. PMID:28880884

Talented football players' development of achievement motives, volitional components, and self-referential cognitions: A longitudinal study.

PubMed

Feichtinger, Philip; Höner, Oliver

2015-01-01

Adolescence is regarded as a key developmental phase in the course of talented football players' careers. The present study focuses on early adolescent players' development of achievement motives, volitional components, and self-referential cognitions. Based on the multidimensional and dynamic nature of talent, the development of multifaceted personality characteristics is an important issue in the context of sports talent research. According to previous findings in psychology, personality characteristics' development is defined by both stability and change, and the current study analyses four different types: differential stability (I), mean-level change (II), individual-level change (III), and structural stability (IV). The sample consists of 151 male players in the talent development programme of the German Football Association. Psychological diagnostics of the personality characteristics are implemented across longitudinal sections over a time period of three seasons, from the U12 to U14 age classes. The results reveal that the personality characteristics show (I) moderate test-retest correlations over one-year intervals (.43 ≤ rtt ≤ .62), and lower coefficients for a two-year period (.26 ≤ rtt ≤ .53). (II) Most of the personality characteristics' mean values differ significantly across the age classes with small effect sizes (.01 ≤ [Formula: see text] ≤ .03). (III) Only minor individual-level changes in the football players' development are found. (IV) The personality characteristics' associations within a two-factor structure do not stay invariant over time. From the results of the present study, conclusions are drawn regarding the talent identification and development process.

Degeneration and Regeneration of Subbasal Corneal Nerves after Infectious Keratitis: A Longitudinal In Vivo Confocal Microscopy Study.

PubMed

Müller, Rodrigo T; Abedi, Farshad; Cruzat, Andrea; Witkin, Deborah; Baniasadi, Neda; Cavalcanti, Bernardo M; Jamali, Arsia; Chodosh, James; Dana, Reza; Pavan-Langston, Deborah; Hamrah, Pedram

2015-11-01

To investigate the longitudinal alterations of subbasal corneal nerves in patients with infectious keratitis (IK) during the acute phase, cessation of treatment, and the recovery phase by in vivo confocal microscopy (IVCM). Prospective, longitudinal, case-control, single-center study. Fifty-six eyes of 56 patients with the diagnosis of bacterial (n=28), fungal (n=15), or Acanthamoeba (n=13) keratitis were included in the study. Thirty eyes of 30 normal volunteers constituted the control group. Corneal sensation and serial IVCM of the central cornea were performed prospectively using the Heidelberg Retina Tomograph 3/Rostock Cornea Module (Heidelberg Engineering, Heidelberg, Germany). The IVCM images were assessed at 3 time points: at the acute phase (first visit to the cornea service), at cessation of antimicrobial treatment, and up to 6 months after the resolution of infection. Total nerve number and length, main nerve trunks, branching, and corneal sensation were assessed during the follow-up period. Corneal nerves were reduced significantly during the acute phase in eyes with IK compared with controls across all subgroups, with total nerve length of 5.47±0.69 mm/mm2 versus 20.59±1.06 mm/mm2 (P<0.0001). At the cessation of treatment, corneal nerves in patients with IK had regenerated, including total nerve length (8.49±0.94 mm/mm2; P=0.02) and nerve branch length (4.80±0.37 mm/mm2; P=0.005). During the recovery phase, after resolution of infection, corneal nerves regenerated further, including total nerve length (12.13±1.97 mm/mm2; P=0.005), main nerve trunk length (5.80±1.00 mm/mm2; P=0.01), and nerve branch length (6.33±0.76 mm/mm2; P=0.003) as compared with the acute phase, but were still significantly lower when compared with controls (P<0.05 for all parameters). Corneal degeneration and regeneration correlated with corneal sensation (r=0.47; P=0.0009). Patients with IK who sustain profound loss of corneal nerves during the acute phase of infection demonstrate increased corneal nerve density during the first 6 months after the resolution of infection. However, despite significant nerve regeneration, corneal nerve density does not recover fully and remains low compared to controls. By providing an objective methodology to monitor corneal re-innervation, IVCM adds potentially important findings that may have implications for clinical management and surgical planning. Copyright © 2015 American Academy of Ophthalmology. Published by Elsevier Inc. All rights reserved.

Subterahertz Longitudinal Phonon Modes Propagating in a Lipid Bilayer Immersed in an Aqueous Medium

NASA Astrophysics Data System (ADS)

Zakhvataev, V. E.

2018-04-01

The properties of subterahertz longitudinal acoustic phonon modes in the hydrophobic region of a lipid bilayer immersed in a compressible viscous aqueous medium are investigated theoretically. An approximate expression is obtained for the Mandelstam-Brillouin components of the dynamic structure factor of a bilayer. The analysis is based on a generalized hydrodynamic model of the "two-dimensional lipid bilayer + three-dimensional fluid medium" system, as well as on known sharp estimates for the frequencies and lifetimes of long-wavelength longitudinal acoustic phonons in a free hydrated lipid bilayer and in water, obtained from inelastic X-ray scattering experiments and molecular dynamics simulations. It is shown that, for characteristic values of the parameters of the membrane system, subterahertz longitudinal phonon-like excitations in the hydrophobic part of the bilayer are underdamped. In this case, the contribution of the viscous flow of the aqueous medium to the damping of a longitudinal membrane mode is small compared with the contribution of the lipid bilayer. Quantitative estimates of the damping ratio agree well with the experimental results for the vibration mode of the enzyme lysozyme in aqueous solution [1]. It is also shown that a coupling between longitudinal phonon modes of the bilayer and relaxation processes in its fluid environment gives rise to an additional peak in the scattering spectrum, which corresponds to a non-propagating mode.

Facilitating Research in Physician Assistant Programs: Creating a Student-Level Longitudinal Database.

PubMed

Morgan, Perri; Humeniuk, Katherine M; Everett, Christine M

2015-09-01

As physician assistant (PA) roles expand and diversify in the United States and around the world, there is a pressing need for research that illuminates how PAs may best be selected, educated, and used in health systems to maximize their potential contributions to health. Physician assistant education programs are well positioned to advance this research by collecting and organizing data on applicants, students, and graduates. Our PA program is creating a permanent longitudinal education database for research that contains extensive student-level data. This database will allow us to conduct research on all phases of PA education, from admission processes through the professional practice of our graduates. In this article, we describe our approach to constructing a longitudinal student-level research database and discuss the strengths and limitations of longitudinal databases for research on education and the practice of PAs. We hope to encourage other PA programs to initiate similar projects so that, in the future, data can be combined for use in multi-institutional research that can contribute to improved education for PA students across programs.

Simplified Aircraft-Based Paired Approach: Concept Definition and Initial Analysis

NASA Technical Reports Server (NTRS)

Johnson, Sally C.; Lohr, Gary W.; McKissick, Burnell T.; Abbott, Terence S.; Geurreiro, Nelson M.; Volk, Paul

2013-01-01

Simplified Aircraft-based Parallel Approach (SAPA) is an advanced concept proposed by the Federal Aviation Administration (FAA) to support dependent parallel approach operations to runways with lateral spacing closer than 2500 ft. At the request of the FAA, NASA performed an initial assessment of the potential performance and feasibility of the SAPA concept, including developing and assessing an operational implementation of the concept and conducting a Monte Carlo wake simulation study to examine the longitudinal spacing requirements. The SAPA concept was shown to have significant operational advantages in supporting the pairing of aircraft with dissimilar final approach speeds. The wake simulation study showed that support for dissimilar final approach speeds could be significantly enhanced through the use of a two-phased altitudebased longitudinal positioning requirement, with larger longitudinal positioning allowed for higher altitudes out of ground effect and tighter longitudinal positioning defined for altitudes near and in ground effect. While this assessment is preliminary and there are a number of operational issues still to be examined, it has shown the basic SAPA concept to be technically and operationally feasible.

Longitudinal development of muons in large air showers studies from the arrival time distributions measured at 900m above sea level

NASA Technical Reports Server (NTRS)

Kakimoto, F.; Tsuchimoto, I.; Enoki, T.; Suga, K.; Nishi, K.

1985-01-01

The arrival time distributions of muons with energies above 1.0GeV and 0.5GeV have been measured in the Akeno air-shower array to study the longitudinal development of muons in air showers with primary energies in the range 10 to the 17th power to 10 to the 18th power ev. The average rise times of muons with energies above 1.0GeV at large core distances are consistent with those expected from very high multiplicity models and, on the contrary, with those expected from the low multiplicity models at small core distances. This implies that the longitudinal development at atmospheric depth smaller than 500 cm square is very fast and that at larger atmospheric depths is rather slow.

The dichotomy between strong and ultra-weak magnetic fields among intermediate-mass stars

NASA Astrophysics Data System (ADS)

Lignières, François; Petit, Pascal; Aurière, Michel; Wade, Gregg A.; Böhm, Torsten

2014-08-01

Until recently, the detection of magnetic fields at the surface of intermediate-mass main-sequence stars has been limited to Ap/Bp stars, a class of chemically peculiar stars. This class represents no more than 5-10% of the stars in this mass range. This small fraction is not explained by the fossil field paradigm that describes the Ap/Bp type magnetism as a remnant of an early phase of the star-life. Also, the limitation of the field measurements to a small and special group of stars is obviously a problem to study the effect of the magnetic fields on the stellar evolution of a typical intermediate-mass star. Thanks to the improved sensitivity of a new generation of spectropolarimeters, a lower bound to the magnetic fields of Ap/Bp stars, a two orders of magnitude desert in the longitudinal magnetic field and a new type of sub-gauss magnetism first discovered on Vega have been identified. These advances provide new clues to understand the origin of intermediate-mass magnetism as well as its influence on stellar evolution. In particular, a scenario has been proposed whereby the magnetic dichotomy between Ap/Bp and Vega-like magnetism originate from the bifurcation between stable and unstable large scale magnetic configurations in differentially rotating stars. In this paper, we review these recent observational findings and discuss this scenario.

Pathogenesis of Hepatitis C Virus Infection in Tupaia belangeri▿†

PubMed Central

Amako, Yutaka; Tsukiyama-Kohara, Kyoko; Katsume, Asao; Hirata, Yuichi; Sekiguchi, Satoshi; Tobita, Yoshimi; Hayashi, Yukiko; Hishima, Tsunekazu; Funata, Nobuaki; Yonekawa, Hiromichi; Kohara, Michinori

2010-01-01

The lack of a small-animal model has hampered the analysis of hepatitis C virus (HCV) pathogenesis. The tupaia (Tupaia belangeri), a tree shrew, has shown susceptibility to HCV infection and has been considered a possible candidate for a small experimental model of HCV infection. However, a longitudinal analysis of HCV-infected tupaias has yet to be described. Here, we provide an analysis of HCV pathogenesis during the course of infection in tupaias over a 3-year period. The animals were inoculated with hepatitis C patient serum HCR6 or viral particles reconstituted from full-length cDNA. In either case, inoculation caused mild hepatitis and intermittent viremia during the acute phase of infection. Histological analysis of infected livers revealed that HCV caused chronic hepatitis that worsened in a time-dependent manner. Liver steatosis, cirrhotic nodules, and accompanying tumorigenesis were also detected. To examine whether infectious virus particles were produced in tupaia livers, naive animals were inoculated with sera from HCV-infected tupaias, which had been confirmed positive for HCV RNA. As a result, the recipient animals also displayed mild hepatitis and intermittent viremia. Quasispecies were also observed in the NS5A region, signaling phylogenic lineage from the original inoculating sequence. Taken together, these data suggest that the tupaia is a practical animal model for experimental studies of HCV infection. PMID:19846521

Effect of growth ring orientation and placement of earlywood and latewood on MOE and MOR of very-small clear Douglas-fir beams.

Treesearch

Amy T. Grotta; Robert J. Leichti; Barbara L. Gartner; G.R. Johnson

2005-01-01

ASTM standard sizes for bending tests (either 50 x 50 mm or 25 x 25 mm in cross-section) are not always suitable for research purposes that characterize smaller sections of wood. Moreover, the ASTM standards specify loading the sample on the longitudinal-tangential surface. If specimens are small enough, then the effects of both growth-ring orientation and whether...

Substantial Churn In Health Insurance Offerings By Small Employers, 2014-15.

PubMed

Vistnes, Jessica P; Rohde, Frederick; Miller, G Edward; Cooper, Philip F

2017-09-01

New data for 2014-15 from the Medical Expenditure Panel Survey-Insurance Component longitudinal survey show substantial churn in insurance offers by small employers (those with fifty or fewer workers), with 14.6 percent of employers that offered insurance in 2014 having dropped it in 2015 and 5.5 percent of those that did not offer it adding coverage. Project HOPE—The People-to-People Health Foundation, Inc.

Working in small-scale, homelike dementia care: effects on staff burnout symptoms and job characteristics. A quasi-experimental, longitudinal study.

PubMed

Zwakhalen, Sandra Mg; Hamers, Jan Ph; van Rossum, Erik; Ambergen, Ton; Kempen, Gertrudis Ijm; Verbeek, Hilde

2018-05-01

This paper reports on a quasi-experimental, longitudinal study on the effects of working in a new type of dementia care facility (i.e. small-scale living facilities) on staff burnout symptoms and job characteristics (job autonomy, social support, physical demands and workload). It is hypothesised that nursing staff working in small-scale facilities experience fewer burnout symptoms, more autonomy and social support, and fewer symptoms of physical demands and workload compared with staff in regular wards. Two types of long-term institutional nursing care settings were included: 28 houses in small-scale living facilities and 21 regular psychogeriatric wards in nursing homes. At baseline and at follow-ups after 6 and 12 months nursing staff were assessed by means of self-report questionnaires. In total, 305 nursing staff members were included in the study, 114 working in small-scale living facilities (intervention group) and 191 in regular wards (control group). No overall effects on burnout symptoms were detected. Significantly fewer physical demands and lower workload were experienced by staff working in small-scale living facilities compared with staff in regular wards. They also experienced more job autonomy. No significant effect was found for overall social support in the total group. This study suggests positive effects of the work environment on several work characteristics. Organisational climate differs in the two conditions, which might account for our results. This may influence nursing staff well-being and has important implications for nursing home managers and policy makers. Future studies should enhance our understanding of the influence of job characteristics on outcomes.

Brachial artery vasomotion and transducer pressure effect on measurements by active contour segmentation on ultrasound

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cary, Theodore W.; Sultan, Laith R.; Sehgal, Chandra M., E-mail: sehgalc@uphs.upenn.edu

Purpose: To use feed-forward active contours (snakes) to track and measure brachial artery vasomotion on ultrasound images recorded in both transverse and longitudinal views; and to compare the algorithm's performance in each view. Methods: Longitudinal and transverse view ultrasound image sequences of 45 brachial arteries were segmented by feed-forward active contour (FFAC). The segmented regions were used to measure vasomotion artery diameter, cross-sectional area, and distention both as peak-to-peak diameter and as area. ECG waveforms were also simultaneously extracted frame-by-frame by thresholding a running finite-difference image between consecutive images. The arterial and ECG waveforms were compared as they traced eachmore » phase of the cardiac cycle. Results: FFAC successfully segmented arteries in longitudinal and transverse views in all 45 cases. The automated analysis took significantly less time than manual tracing, but produced superior, well-behaved arterial waveforms. Automated arterial measurements also had lower interobserver variability as measured by correlation, difference in mean values, and coefficient of variation. Although FFAC successfully segmented both the longitudinal and transverse images, transverse measurements were less variable. The cross-sectional area computed from the longitudinal images was 27% lower than the area measured from transverse images, possibly due to the compression of the artery along the image depth by transducer pressure. Conclusions: FFAC is a robust and sensitive vasomotion segmentation algorithm in both transverse and longitudinal views. Transverse imaging may offer advantages over longitudinal imaging: transverse measurements are more consistent, possibly because the method is less sensitive to variations in transducer pressure during imaging.« less

Brachial artery vasomotion and transducer pressure effect on measurements by active contour segmentation on ultrasound.

PubMed

Cary, Theodore W; Reamer, Courtney B; Sultan, Laith R; Mohler, Emile R; Sehgal, Chandra M

2014-02-01

To use feed-forward active contours (snakes) to track and measure brachial artery vasomotion on ultrasound images recorded in both transverse and longitudinal views; and to compare the algorithm's performance in each view. Longitudinal and transverse view ultrasound image sequences of 45 brachial arteries were segmented by feed-forward active contour (FFAC). The segmented regions were used to measure vasomotion artery diameter, cross-sectional area, and distention both as peak-to-peak diameter and as area. ECG waveforms were also simultaneously extracted frame-by-frame by thresholding a running finite-difference image between consecutive images. The arterial and ECG waveforms were compared as they traced each phase of the cardiac cycle. FFAC successfully segmented arteries in longitudinal and transverse views in all 45 cases. The automated analysis took significantly less time than manual tracing, but produced superior, well-behaved arterial waveforms. Automated arterial measurements also had lower interobserver variability as measured by correlation, difference in mean values, and coefficient of variation. Although FFAC successfully segmented both the longitudinal and transverse images, transverse measurements were less variable. The cross-sectional area computed from the longitudinal images was 27% lower than the area measured from transverse images, possibly due to the compression of the artery along the image depth by transducer pressure. FFAC is a robust and sensitive vasomotion segmentation algorithm in both transverse and longitudinal views. Transverse imaging may offer advantages over longitudinal imaging: transverse measurements are more consistent, possibly because the method is less sensitive to variations in transducer pressure during imaging.

Brachial artery vasomotion and transducer pressure effect on measurements by active contour segmentation on ultrasound

PubMed Central

Cary, Theodore W.; Reamer, Courtney B.; Sultan, Laith R.; Mohler, Emile R.; Sehgal, Chandra M.

2014-01-01

Purpose: To use feed-forward active contours (snakes) to track and measure brachial artery vasomotion on ultrasound images recorded in both transverse and longitudinal views; and to compare the algorithm's performance in each view. Methods: Longitudinal and transverse view ultrasound image sequences of 45 brachial arteries were segmented by feed-forward active contour (FFAC). The segmented regions were used to measure vasomotion artery diameter, cross-sectional area, and distention both as peak-to-peak diameter and as area. ECG waveforms were also simultaneously extracted frame-by-frame by thresholding a running finite-difference image between consecutive images. The arterial and ECG waveforms were compared as they traced each phase of the cardiac cycle. Results: FFAC successfully segmented arteries in longitudinal and transverse views in all 45 cases. The automated analysis took significantly less time than manual tracing, but produced superior, well-behaved arterial waveforms. Automated arterial measurements also had lower interobserver variability as measured by correlation, difference in mean values, and coefficient of variation. Although FFAC successfully segmented both the longitudinal and transverse images, transverse measurements were less variable. The cross-sectional area computed from the longitudinal images was 27% lower than the area measured from transverse images, possibly due to the compression of the artery along the image depth by transducer pressure. Conclusions: FFAC is a robust and sensitive vasomotion segmentation algorithm in both transverse and longitudinal views. Transverse imaging may offer advantages over longitudinal imaging: transverse measurements are more consistent, possibly because the method is less sensitive to variations in transducer pressure during imaging. PMID:24506648

Salary, Performance, and Superintendent Turnover

ERIC Educational Resources Information Center

Grissom, Jason A.; Mitani, Hajime

2016-01-01

Purpose: Superintendent retention is an important goal for many school districts, yet the factors contributing to superintendent turnover are poorly understood. Most prior quantitative studies of superintendent turnover have relied on small, cross-sectional samples, limiting the evidence base. Utilizing longitudinal administrative records from…

Teaching Science.

ERIC Educational Resources Information Center

Leyden, Michael

1996-01-01

Describes use of a sundial to study Earth's orbit and time. Covers construction of sundial, exploration phase, introduction of concept of time as determined by the position of the sun in relation to the observer's meridian, comparison of sundial time and wristwatch time, longitudinal corrections, introduction of orbital corrections, and further…

C-Peptide Decline in Type 1 Diabetes Has Two Phases: An Initial Exponential Fall and a Subsequent Stable Phase.

PubMed

Shields, Beverley M; McDonald, Timothy J; Oram, Richard; Hill, Anita; Hudson, Michelle; Leete, Pia; Pearson, Ewan R; Richardson, Sarah J; Morgan, Noel G; Hattersley, Andrew T

2018-06-07

The decline in C-peptide in the 5 years after diagnosis of type 1 diabetes has been well studied, but little is known about the longer-term trajectory. We aimed to examine the association between log-transformed C-peptide levels and the duration of diabetes up to 40 years after diagnosis. We assessed the pattern of association between urinary C-peptide/creatinine ratio (UCPCR) and duration of diabetes in cross-sectional data from 1,549 individuals with type 1 diabetes using nonlinear regression approaches. Findings were replicated in longitudinal follow-up data for both UCPCR ( n = 161 individuals, 326 observations) and plasma C-peptide ( n = 93 individuals, 473 observations). We identified two clear phases of C-peptide decline: an initial exponential fall over 7 years (47% decrease/year [95% CI -51%, -43%]) followed by a stable period thereafter (+0.07%/year [-1.3, +1.5]). The two phases had similar durations and slopes in patients above and below the median age at diagnosis (10.8 years), although levels were lower in the younger patients irrespective of duration. Patterns were consistent in both longitudinal UCPCR ( n = 162; ≤7 years duration: -48%/year [-55%, -38%]; >7 years duration -0.1% [-4.1%, +3.9%]) and plasma C-peptide ( n = 93; >7 years duration only: -2.6% [-6.7%, +1.5%]). These data support two clear phases of C-peptide decline: an initial exponential fall over a 7-year period, followed by a prolonged stabilization where C-peptide levels no longer decline. Understanding the pathophysiological and immunological differences between these two phases will give crucial insights into understanding β-cell survival. © 2018 by the American Diabetes Association.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ratner, D.; Behrens, C.; Ding, Y.

The microbunching instability (MBI) is a well known problem for high brightness electron beams and has been observed at accelerator facilities around the world. Free-electron lasers (FELs) are particularly susceptible to MBI, which can distort the longitudinal phase space and increase the beam’s slice energy spread (SES). Past studies of MBI at the Linac Coherent Light Source (LCLS) relied on optical transition radiation to infer the existence of microbunching. With the development of the x-band transverse deflecting cavity (XTCAV), we can for the first time directly image the longitudinal phase space at the end of the accelerator and complete amore » comprehensive study of MBI, revealing both detailed MBI behavior as well as insights into mitigation schemes. The fine time resolution of the XTCAV also provides the first LCLS measurements of the final SES, a critical parameter for many advanced FEL schemes. As a result, detailed MBI and SES measurements can aid in understanding MBI mechanisms, benchmarking simulation codes, and designing future high- brightness accelerators.« less

Nonlinear stability and control study of highly maneuverable high performance aircraft

NASA Technical Reports Server (NTRS)

Mohler, R. R.

1993-01-01

This project is intended to research and develop new nonlinear methodologies for the control and stability analysis of high-performance, high angle-of-attack aircraft such as HARV (F18). Past research (reported in our Phase 1, 2, and 3 progress reports) is summarized and more details of final Phase 3 research is provided. While research emphasis is on nonlinear control, other tasks such as associated model development, system identification, stability analysis, and simulation are performed in some detail as well. An overview of various models that were investigated for different purposes such as an approximate model reference for control adaptation, as well as another model for accurate rigid-body longitudinal motion is provided. Only a very cursory analysis was made relative to type 8 (flexible body dynamics). Standard nonlinear longitudinal airframe dynamics (type 7) with the available modified F18 stability derivatives, thrust vectoring, actuator dynamics, and control constraints are utilized for simulated flight evaluation of derived controller performance in all cases studied.

Microbunching-instability-induced sidebands in a seeded free-electron laser

DOE PAGES

Zhang, Zhen; Lindberg, Ryan; Fawley, William M.; ...

2016-05-02

Measurements of the multishot-averaged, soft x-ray, self-seeding spectrum at the LCLS free-electron laser often have a pedestal-like distribution around the seeded wavelength, which limits the spectral purity and can negatively affect some user applications not employing a post-undulator monochromator. In this paper, we study the origins of such pedestals, focusing on longitudinal phase space modulations produced by the microbunching instability upstream of the free-electron laser (FEL) undulator. Furthermore, we show from theory and numerical simulation that both energy and density modulations can induce sidebands in a high-gain, seeded FEL whose fractional strength typically grows as the square of the undulatormore » length. The results place a tight constraint on the longitudinal phase space uniformity of the electron beam for a seeded FEL, possibly requiring the amplitude of long-wavelength modulations to be much smaller than the typical incoherent energy spread if the output sideband power is to remain only a couple percent or less of the amplified seed power.« less

Measurement of the longitudinal and circumferential muscular activity associated with peristalsis using a single fibre grating array

NASA Astrophysics Data System (ADS)

Arkwright, J. W.; Blenman, N. G.; Underhill, I. D.; Maunder, S. A.; Spencer, N. J.; Costa, M.; Brooks, S. J.; Szczesniak, M. M.; Dinning, P. G.

2010-09-01

Diagnostic catheters based on fibre Bragg gratings (FBG's) are proving to be highly effective for measurement of the muscular activity associated with peristalsis in the human gut. The primary muscular contractions that generate peristalsis are circumferential in nature; however, it has long been known that there is also a component of longitudinal contractility present, acting in harmony with the circumferential component to improve the overall efficiency of material movement. To date, there have been relatively few reports on the measurement or inference of longitudinal contractions in humans and all have been limited to detection at a single location only. This is due to the lack of a viable recording technique suitable for real-time in-vivo measurement of this type of activity over extended lengths of the gut. We report the detection of longitudinal motion in lengths of excised mammalian colon using an FBG technique that should be viable for similar detection in humans. The longitudinal sensors have been combined with our previously reported FBG pressure sensing elements to form a composite catheter that allows the relative phase between the two components to be detected. The catheter output has been validated using digital video mapping in an ex-vivo animal preparation using lengths of rabbit ileum.

Optimising qualitative longitudinal analysis: Insights from a study of traumatic brain injury recovery and adaptation.

PubMed

Fadyl, Joanna K; Channon, Alexis; Theadom, Alice; McPherson, Kathryn M

2017-04-01

Knowledge about aspects that influence recovery and adaptation in the postacute phase of disabling health events is key to understanding how best to provide appropriate rehabilitation and health services. Qualitative longitudinal research makes it possible to look for patterns, key time points and critical moments that could be vital for interventions and supports. However, strategies that support robust data management and analysis for longitudinal qualitative research in health-care are not well documented in the literature. This article reviews three challenges encountered in a large longitudinal qualitative descriptive study about experiences of recovery and adaptation after traumatic brain injury in New Zealand, and the strategies and technologies used to address them. These were (i) tracking coding and analysis decisions during an extended analysis period; (ii) navigating interpretations over time and in response to new data; and (iii) exploiting data volume and complexity. Concept mapping during coding review, a considered combination of information technologies, employing both cross-sectional and narrative analysis, and an expectation that subanalyses would be required for key topics helped us manage the study in a way that facilitated useful and novel insights. These strategies could be applied in other qualitative longitudinal studies in healthcare inquiry to optimise data analysis and stimulate important insights. © 2016 John Wiley & Sons Ltd.

A Novel Strategy for Continuation ECT in Geriatric Depression: Phase 2 of the PRIDE Study.

PubMed

Kellner, Charles H; Husain, Mustafa M; Knapp, Rebecca G; McCall, W Vaughn; Petrides, Georgios; Rudorfer, Matthew V; Young, Robert C; Sampson, Shirlene; McClintock, Shawn M; Mueller, Martina; Prudic, Joan; Greenberg, Robert M; Weiner, Richard D; Bailine, Samuel H; Rosenquist, Peter B; Raza, Ahmad; Kaliora, Styliani; Latoussakis, Vassilios; Tobias, Kristen G; Briggs, Mimi C; Liebman, Lauren S; Geduldig, Emma T; Teklehaimanot, Abeba A; Dooley, Mary; Lisanby, Sarah H

2016-11-01

The randomized phase (phase 2) of the Prolonging Remission in Depressed Elderly (PRIDE) study evaluated the efficacy and tolerability of continuation ECT plus medication compared with medication alone in depressed geriatric patients after a successful course of ECT (phase 1). PRIDE was a two-phase multisite study. Phase 1 was an acute course of right unilateral ultrabrief pulse ECT, augmented with venlafaxine. Phase 2 compared two randomized treatment arms: a medication only arm (venlafaxine plus lithium, over 24 weeks) and an ECT plus medication arm (four continuation ECT treatments over 1 month, plus additional ECT as needed, using the Symptom-Titrated, Algorithm-Based Longitudinal ECT [STABLE] algorithm, while continuing venlafaxine plus lithium). The intent-to-treat sample comprised 120 remitters from phase 1. The primary efficacy outcome measure was score on the 24-item Hamilton Depression Rating Scale (HAM-D), and the secondary efficacy outcome was score on the Clinical Global Impressions severity scale (CGI-S). Tolerability as measured by neurocognitive performance (reported elsewhere) was assessed using an extensive test battery; global cognitive functioning as assessed by the Mini-Mental State Examination (MMSE) is reported here. Longitudinal mixed-effects repeated-measures modeling was used to compare ECT plus medication and medication alone for efficacy and global cognitive function outcomes. At 24 weeks, the ECT plus medication group had statistically significantly lower HAM-D scores than the medication only group. The difference in adjusted mean HAM-D scores at study end was 4.2 (95% CI=1.6, 6.9). Significantly more patients in the ECT plus medication group were rated "not ill at all" on the CGI-S compared with the medication only group. There was no statistically significant difference between groups in MMSE score. Additional ECT after remission (here operationalized as four continuation ECT treatments followed by further ECT only as needed) was beneficial in sustaining mood improvement for most patients.

One-shot and aberration-tolerable homodyne detection for holographic storage readout through double-frequency grating-based lateral shearing interferometry.

PubMed

Yu, Yeh-Wei; Xiao, Shuai; Cheng, Chih-Yuan; Sun, Ching-Cherng

2016-05-16

A simple method to decode the stored phase signal of volume holographic data storage with adequate wave aberration tolerance is highly demanded. We proposed and demonstrated a one-shot scheme to decode a binary-phase encoding signal through double-frequency-grating based shearing interferometry (DFGSI). The lateral shearing amount is dependent on the focal length of the collimated lens and the frequency difference between the gratings. Diffracted waves with phase encoding were successfully decoded through experimentation. An optical model for the DFGSI was built to analyze phase-error induction and phase-difference control by shifting the double-frequency grating longitudinally and laterally, respectively. The optical model was demonstrated experimentally. Finally, a high aberration tolerance of the DFGSI was demonstrated using the optical model.

Spatially resolved photodiode response for simulating precise interferometers.

PubMed

Fernández Barranco, Germán; Tröbs, Michael; Müller, Vitali; Gerberding, Oliver; Seifert, Frank; Heinzel, Gerhard

2016-08-20

Quadrant photodiodes (QPDs) are used in laser interferometry systems to simultaneously detect longitudinal displacement of test masses and angular misalignment between the two interfering beams. The latter is achieved by means of the differential wavefront sensing (DWS) technique, which provides ultra-high precision for measuring angular displacements. We have developed a setup to obtain the spatially resolved response of QPDs that, together with an extension of the simulation software IfoCAD, allows us to use the measured response in simulations and accurately predict the desired longitudinal and DWS phase observables. Three different commercial off-the-shelf QPD candidates for space-based interferometry were characterized. The measured response of one QPD was used in optical simulations. Nonuniformities in the response of the device and crosstalk between segments do not introduce significant variations in the longitudinal and DWS measurands with respect to the standard case when a uniform QPD without crosstalk is used.

7 CFR 3403.4 - Three-phase program.

Code of Federal Regulations, 2010 CFR

2010-01-01

..., AND EXTENSION SERVICE, DEPARTMENT OF AGRICULTURE SMALL BUSINESS INNOVATION RESEARCH GRANTS PROGRAM Program Description § 3403.4 Three-phase program. The Small Business Innovation Research Grants Program is... technical merit and feasibility of the proposed effort and the quality of performance of the small business...

Acceleration of the loss of the first-phase insulin response during the progression to type 1 diabetes in diabetes prevention trial-type 1 participants.

PubMed

Sosenko, Jay M; Skyler, Jay S; Beam, Craig A; Krischer, Jeffrey P; Greenbaum, Carla J; Mahon, Jeffrey; Rafkin, Lisa E; Matheson, Della; Herold, Kevan C; Palmer, Jerry P

2013-12-01

We studied the change in the first-phase insulin response (FPIR) during the progression to type 1 diabetes (T1D). Seventy-four oral insulin trial progressors to T1D from the Diabetes Prevention Trial-Type 1 with at least one FPIR measurement after baseline and before diagnosis were studied. The FPIR was examined longitudinally in 26 progressors who had FPIR measurements during each of the 3 years before diagnosis. The association between the change from the baseline FPIR to the last FPIR and time to diagnosis was studied in the remainder (n = 48). The 74 progressors had lower baseline FPIR values than nonprogressors (n = 270), with adjustments made for age and BMI. In the longitudinal analysis of the 26 progressors, there was a greater decline in the FPIR from 1.5 to 0.5 years before diagnosis than from 2.5 to 1.5 years before diagnosis. This accelerated decline was also evident in a regression analysis of the 48 remaining progressors in whom the rate of decline became more marked with the approaching diagnosis. The patterns of decline were similar between the longitudinal and regression analyses. There is an acceleration of decline in the FPIR during the progression to T1D, which becomes especially marked between 1.5 and 0.5 years before diagnosis.

Determinants and impact of suboptimal asthma control in Europe: The INTERNATIONAL CROSS-SECTIONAL AND LONGITUDINAL ASSESSMENT ON ASTHMA CONTROL (LIAISON) study.

PubMed

Braido, Fulvio; Brusselle, Guy; Guastalla, Daniele; Ingrassia, Eleonora; Nicolini, Gabriele; Price, David; Roche, Nicolas; Soriano, Joan B; Worth, Heinrich

2016-05-14

According to the Global Initiative of Asthma, the aim of asthma treatment is to gain and maintain control. In the INTERNATIONAL CROSS-SECTIONAL AND LONGITUDINAL ASSESSMENT ON ASTHMA CONTROL (LIAISON) study, we evaluated the level of asthma control and quality of life (QoL), as well as their determinants and impact in a population consulting specialist settings. LIAISON is a prospective, multicentre, observational study with a cross-sectional and a 12-month longitudinal phase. Adults with an asthma diagnosis since at least 6 months, receiving the same asthma treatment in the 4 weeks before enrolment were included. Asthma control was assessed with the 6-item Asthma Control Questionnaire (ACQ) and QoL with the MiniAsthma Quality of Life Questionnaire (MiniAQLQ). Overall, 8111 asthmatic patients were enrolled in 12 European countries. Asthma control was suboptimal in 56.5 % of patients and it was associated with poorer asthma-related QoL, higher risk of exacerbations and greater consumption of healthcare resources. Variables associated with suboptimal control were age, gender, obesity, smoking and comorbidities. Major determinants of poor asthma control were seasonal worsening and persisting exposure to allergens/irritants/triggers, followed by treatment-related issues. The cross-sectional phase results confirm that suboptimal control is frequent and has a high individual and economic impact. The clinicaltrials.gov identifier is NCT01567280 .

Modulational instability of finite-amplitude, circularly polarized Alfven waves

NASA Technical Reports Server (NTRS)

Derby, N. F., Jr.

1978-01-01

The simple theory of the decay instability of Alfven waves is strictly applicable only to a small-amplitude parent wave in a low-beta plasma, but, if the parent wave is circularly polarized, it is possible to analyze the situation without either of these restrictions. Results show that a large-amplitude circularly polarized wave is unstable with respect to decay into three waves, one longitudinal and one transverse wave propagating parallel to the parent wave and one transverse wave propagating antiparallel. The transverse decay products appear at frequencies which are the sum and difference of the frequencies of the parent wave and the longitudinal wave. The decay products are not familiar MHD modes except in the limit of small beta and small amplitude of the parent wave, in which case the decay products are a forward-propagating sound wave and a backward-propagating circularly polarized wave. In this limit the other transverse wave disappears. The effect of finite beta is to reduce the linear growth rate of the instability from the value suggested by the simple theory. Possible applications of these results to the theory of the solar wind are briefly touched upon.

Incorporation of ionic liquid into porous polymer monoliths to enhance the separation of small molecules in reversed-phase high-performance liquid chromatography.

PubMed

Wang, Jiafei; Bai, Ligai; Wei, Zhen; Qin, Junxiao; Ma, Yamin; Liu, Haiyan

2015-06-01

An ionic liquid was incorporated into the porous polymer monoliths to afford stationary phases with enhanced chromatographic performance for small molecules in reversed-phase high-performance liquid chromatography. The effect of the ionic liquid in the polymerization mixture on the performance of the monoliths was studied in detail. While monoliths without ionic liquid exhibited poor resolution and low efficiency, the addition of ionic liquid to the polymerization mixture provides highly increased resolution and high efficiency. The chromatographic performances of the monoliths were demonstrated by the separations of various small molecules including aromatic hydrocarbons, isomers, and homologues using a binary polar mobile phase. The present column efficiency reached 27 000 plates/m, which showed that the ionic liquid monoliths are alternative stationary phases in the separation of small molecules by high-performance liquid chromatography. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Bayesian hierarchical models for smoothing in two-phase studies, with application to small area estimation.

PubMed

Ross, Michelle; Wakefield, Jon

2015-10-01

Two-phase study designs are appealing since they allow for the oversampling of rare sub-populations which improves efficiency. In this paper we describe a Bayesian hierarchical model for the analysis of two-phase data. Such a model is particularly appealing in a spatial setting in which random effects are introduced to model between-area variability. In such a situation, one may be interested in estimating regression coefficients or, in the context of small area estimation, in reconstructing the population totals by strata. The efficiency gains of the two-phase sampling scheme are compared to standard approaches using 2011 birth data from the research triangle area of North Carolina. We show that the proposed method can overcome small sample difficulties and improve on existing techniques. We conclude that the two-phase design is an attractive approach for small area estimation.

Ultrasonic determination of the elastic constants of the stiffness matrix for unidirectional fiberglass epoxy composites

NASA Technical Reports Server (NTRS)

Marques, E. R. C.; Williams, J. H., Jr.

1986-01-01

The elastic constants of a fiberglass epoxy unidirectional composite are determined by measuring the phase velocities of longitudinal and shear stress waves via the through transmission ultrasonic technique. The waves introduced into the composite specimens were generated by piezoceramic transducers. Geometric lengths and the times required to travel those lengths were used to calculate the phase velocities. The model of the transversely isotropic medium was adopted to relate the velocities and elastic constants.

Zero group velocity longitudinal modes in an isotropic cylinder

NASA Astrophysics Data System (ADS)

Hussain, Takasar; Ahmad, Faiz; Ozair, Muhammad

2018-06-01

Zero group velocity (ZGV) modes are studied in an isotropic cylinder. The L(0, 2) mode behaves anomalously for the materials with a value of the bulk velocity ratio, κ , in the range √{2}<κ <2.64 and normally otherwise. All higher modes, except the first few, have no ZGV point for all isotropic materials. This is explained analytically by finding the slope of phase velocity dispersion curves of modes first when the phase velocity equals κ and then at their initial state.

Phase 2 Performance and Stability Tests of the YF-100A Airplane

DTIC Science & Technology

1953-12-01

substantially reduced by the installation of the yaw damper on all F-100 aircraft. The production effectivity of this installation is F-1000, No. 164, with...longitudinal control system. The merits and effects of this modification have been discussed elsewhere in this report and in WADC comments on Phase IV tests...a position on the shroud effective ship F-lOOA No. 154 and subsequent. Par E, 2s - Refer to comment on Par E, 2b. Par E, 2u - Flight experience

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bhattacharya, S.; Shen, S.Y.; Ketterson, J.B.

Anisotropy in the velocity and attenuation of longitudinal ultrasound was studied for the first time in a stable smectic-B liquid crystal (..beta..-methyl-butyl-methoxybenzylidene amino cinnamate). Anisotropy in the velocity was found to be consistent with the predictions of the Martin-Parodi-Pershan hydrodynamic theory in both smectic-A and -B phases, but was significantly smaller than when measured in the same material by Brillouin scattering. Furthermore, strong dispersion was observed near the smectic-A--smectic-B phase transition for sound propagating perpendicular to the symmetry direction.

Mapping communication spaces: The development and use of a tool for analyzing the impact of EHRs on interprofessional collaborative practice.

PubMed

Rashotte, Judy; Varpio, Lara; Day, Kathy; Kuziemsky, Craig; Parush, Avi; Elliott-Miller, Pat; King, James W; Roffey, Tyson

2016-09-01

Members of the healthcare team must access and share patient information to coordinate interprofessional collaborative practice (ICP). Although some evidence suggests that electronic health records (EHRs) contribute to in-team communication breakdowns, EHRs are still widely hailed as tools that support ICP. If EHRs are expected to promote ICP, researchers must be able to longitudinally study the impact of EHRs on ICP across communication types, users, and physical locations. This paper presents a data collection and analysis tool, named the Map of the Clinical Interprofessional Communication Spaces (MCICS), which supports examining how EHRs impact ICP over time, and across communication types, users, and physical locations. The tool's development evolved during a large prospective longitudinal study conducted at a Canadian pediatric academic tertiary-care hospital. This two-phased study [i.e., pre-implementation (phase 1) and post implementation (phase 2)] of an EHR employed a constructivist grounded theory approach and triangulated data collection strategies (i.e., non-participant observations, interviews, think-alouds, and document analysis). The MCICS was created through a five-step process: (i) preliminary structural development based on the use of the paper-based chart (phase 1); (ii) confirmatory review and modification process (phase 1); (iii) ongoing data collection and analysis facilitated by the map (phase 1); (iv) data collection and modification of map based on impact of EHR (phase 2); and (v) confirmatory review and modification process (phase 2). Creating and using the MCICS enabled our research team to locate, observe, and analyze the impact of the EHR on ICP, (a) across oral, electronic, and paper communications, (b) through a patient's passage across different units in the hospital, (c) across the duration of the patient's stay in hospital, and (d) across multiple healthcare providers. By using the MCICS, we captured a comprehensive, detailed picture of the clinical milieu in which the EHR was implemented, and of the intended and unintended consequences of the EHR's deployment. The map supported our observations and analysis of ICP communication spaces, and of the role of the patient chart in these spaces. If EHRs are expected to help resolve ICP challenges, it is important that researchers be able to longitudinally assess the impact of EHRs on ICP across multiple modes of communication, users, and physical locations. Mapping the clinical communication spaces can help EHR designers, clinicians, educators and researchers understand these spaces, appreciate their complexity, and navigate their way towards effective use of EHRs as means for supporting ICP. We propose that the MCICS can be used "as is" in other academic tertiary-care pediatric hospitals, and can be tailored for use in other healthcare institutions. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

The role of sleep disturbances in the longitudinal relationship between psychosocial working conditions, measured by work demands and support, and depression.

PubMed

Magnusson Hanson, Linda L; Chungkham, Holendro Singh; Åkerstedt, Torbjörn; Westerlund, Hugo

2014-12-01

Because work demands and lack of social support seem to be prospectively linked to sleep problems, and sleep problems are linked to depression, sleep problems may play a role in the relationship between these work characteristics and depressive symptoms. In order to shed more light on this relationship, the current study investigated whether disturbed sleep is a mediator in the longitudinal relationships between work demands, social support, and depression. Longitudinal cohort study with repeated survey measures on four occasions. Swedish workforce. 2,017 working participants from the Swedish Longitudinal Occupational Survey of Health in 2006, 2008, 2010, and 2012. Work demands (four items) and social support (six items) were assessed with the Demand Control Questionnaire, disturbed sleep (four items) with the Karolinska Sleep Questionnaire, and depressive symptoms with a brief subscale (six items) from the Symptom Checklist. Autoregressive longitudinal mediation models using structural equation modeling were tested. The work characteristics, and disturbed sleep, were found to be separately associated with depressive symptoms in subsequent waves. However, only demands were found to be longitudinally related to subsequent disturbed sleep. The longitudinal autoregressive models supported a weak mediating role of disturbed sleep in the relationship between demands and depressive symptoms (standardized beta 0.008, P < 0.001), but not between support and depressive symptoms. These results indicate that higher demands at work might cause an increase in depressive symptoms, in part, by increasing disturbed sleep, although the mediated effect was relatively small compared to the total effect. © 2014 Associated Professional Sleep Societies, LLC.

Teacher-student relationship quality and academic achievement in elementary school: A longitudinal examination of gender differences.

PubMed

Hajovsky, Daniel B; Mason, Benjamin A; McCune, Luke A

2017-08-01

Multiple group longitudinal cross-lagged panel models were implemented to understand the directional influences between teacher-student closeness and conflict and measured math and reading achievement across elementary grades and gender groups using the National Institute of Child Health and Human Development longitudinal sample (N=1133). Specifically, after testing multiple group longitudinal measurement invariance to ensure consistent measurement across genders and time, and tests of equivalence of the latent parameters, we were interested in whether longitudinal changes in teacher-rated closeness and conflict explained longitudinal changes in achievement, and vice versa, and whether those longitudinal influences varied by gender. Latent teacher-student closeness decreased for both genders over time (Cohen's d=-0.15 to -0.32), but latent conflict increased for males (Cohen's d=0.16). There was also increased heterogeneity in teacher-student relationship quality for males relative to females. Math and reading achievement had medium reciprocal effects (β=0.12 to 0.23), and previous math achievement had small to medium effects on subsequent teacher-student closeness (β=0.08 to 0.11) and conflict (β=-0.07 to -0.09). Teacher-student conflict and closeness did not influence subsequent levels of math or reading achievement once previous levels were controlled. Further, these influences were consistent across gender groups despite latent differences in teacher-student closeness and conflict with teachers reporting closer relationships with female students and more conflictual relationships with male students. Copyright © 2017 Society for the Study of School Psychology. Published by Elsevier Ltd. All rights reserved.

Comparison of modified driver circuit and capacitor-transfer circuit in longitudinally excited N2 laser.

PubMed

Uno, Kazuyuki; Akitsu, Tetsuya; Nakamura, Kenshi; Jitsuno, Takahisa

2013-04-01

We developed a modified driver circuit composed of a capacitance and a spark gap, called a direct-drive circuit, for a longitudinally excited gas laser. The direct-drive circuit uses a large discharge impedance caused by a long discharge length of the longitudinal excitation scheme and eliminates the buffer capacitance used in the traditional capacitor-transfer circuit. We compared the direct-drive circuit and the capacitor-transfer circuit in a longitudinally excited N2 laser (wavelength: 337 nm). Producing high output energy with the capacitor-transfer circuit requires a large storage capacitance and a discharge tube with optimum dimensions (an inner diameter of 4 mm and a length of 10 cm in this work); in contrast, the direct-drive circuit requires a high breakdown voltage, achieved with a small storage capacitance and a large discharge tube. Additionally, for the same input energy of 792 mJ, the maximum output energy of the capacitor-transfer circuit was 174.2 μJ, and that of the direct-drive circuit was 344.7 μJ.

Walkability and cardiometabolic risk factors: Cross-sectional and longitudinal associations from the Multi-Ethnic Study of Atherosclerosis.

PubMed

Braun, Lindsay M; Rodríguez, Daniel A; Evenson, Kelly R; Hirsch, Jana A; Moore, Kari A; Diez Roux, Ana V

2016-05-01

We used data from 3227 older adults in the Multi-Ethnic Study of Atherosclerosis (2004-2012) to explore cross-sectional and longitudinal associations between walkability and cardiometabolic risk factors. In cross-sectional analyses, linear regression was used to estimate associations of Street Smart Walk Score® with glucose, triglycerides, HDL and LDL cholesterol, systolic and diastolic blood pressure, and waist circumference, while logistic regression was used to estimate associations with odds of metabolic syndrome. Econometric fixed effects models were used to estimate longitudinal associations of changes in walkability with changes in each risk factor among participants who moved residential locations between 2004 and 2012 (n=583). Most cross-sectional and longitudinal associations were small and statistically non-significant. We found limited evidence that higher walkability was cross-sectionally associated with lower blood pressure but that increases in walkability were associated with increases in triglycerides and blood pressure over time. Further research over longer time periods is needed to understand the potential for built environment interventions to improve cardiometabolic health. Copyright © 2016 Elsevier Ltd. All rights reserved.

Development of a radial-torsional vibration hybrid type ultrasonic motor with a hollow and short cylindrical structure.

PubMed

Wang, Jian; Guo, Jifeng

2009-05-01

A longitudinal-torsional hybrid-type ultrasonic motor has larger torque and lower revolution speed compared with other kinds of ultrasonic motors. It drives devices directly and precisely, so it is adaptable to many fields, especially aeronautics and astronautics, as a servo actuator. Due to the different sound propagation speeds of longitudinal and torsional vibrations in the stator, it is difficult to match resonant frequencies of longitudinal and torsional vibrations. In this paper, a new radial-torsional vibration hybrid-type ultrasonic motor is put forward, which utilizes longitudinal vibration derived from radial vibration by the Poisson effect. The short, hollow cylindrical structure easily makes resonant frequencies of first-order radial and torsional vibrations into degeneracy. First, the new structure of the motor is presented. Second, the principle of matching the resonant frequencies is developed, and the motor geometry is optimized by ANSYS software. Finally, a 60-mm diameter prototype is fabricated, which performs well. The no-load velocity and maximum torque are 25 r/min and 5 N x m, respectively. This kind of motor is small, light, and noiseless.

Longitudinal, transcranial measurement of functional activation in the rat brain by diffuse correlation spectroscopy.

PubMed

Blanco, Igor; Zirak, Peyman; Dragojević, Tanja; Castellvi, Clara; Durduran, Turgut; Justicia, Carles

2017-10-01

Neural activity is an important biomarker for the presence of neurodegenerative diseases, cerebrovascular alterations, and brain trauma; furthermore, it is a surrogate marker for treatment effects. These pathologies may occur and evolve in a long time-period, thus, noninvasive, transcutaneous techniques are necessary to allow a longitudinal follow-up. In the present work, we have customized noninvasive, transcutaneous, diffuse correlation spectroscopy (DCS) to localize changes in cerebral blood flow (CBF) induced by neural activity. We were able to detect changes in CBF in the somatosensory cortex by using a model of electrical forepaw stimulation in rats. The suitability of DCS measurements for longitudinal monitoring was demonstrated by performing multiple sessions with the same animals at different ages (from 6 to 18 months). In addition, functional DCS has been cross-validated by comparison with functional magnetic resonance imaging (fMRI) in the same animals in a subset of the time-points. The overall results obtained with transcutaneous DCS demonstrates that it can be utilized in longitudinal studies safely and reproducibly to locate changes in CBF induced by neural activity in the small animal brain.

Coupled changes in brain white matter microstructure and fluid intelligence in later life.

PubMed

Ritchie, Stuart J; Bastin, Mark E; Tucker-Drob, Elliot M; Maniega, Susana Muñoz; Engelhardt, Laura E; Cox, Simon R; Royle, Natalie A; Gow, Alan J; Corley, Janie; Pattie, Alison; Taylor, Adele M; Valdés Hernández, Maria Del C; Starr, John M; Wardlaw, Joanna M; Deary, Ian J

2015-06-03

Understanding aging-related cognitive decline is of growing importance in aging societies, but relatively little is known about its neural substrates. Measures of white matter microstructure are known to correlate cross-sectionally with cognitive ability measures, but only a few small studies have tested for longitudinal relations among these variables. We tested whether there were coupled changes in brain white matter microstructure indexed by fractional anisotropy (FA) and three broad cognitive domains (fluid intelligence, processing speed, and memory) in a large cohort of human participants with longitudinal diffusion tensor MRI and detailed cognitive data taken at ages 73 years (n = 731) and 76 years (n = 488). Longitudinal changes in white matter microstructure were coupled with changes in fluid intelligence, but not with processing speed or memory. Individuals with higher baseline white matter FA showed less subsequent decline in processing speed. Our results provide evidence for a longitudinal link between changes in white matter microstructure and aging-related cognitive decline during the eighth decade of life. They are consistent with theoretical perspectives positing that a corticocortical "disconnection" partly explains cognitive aging. Copyright © 2015 Ritchie et al.

Poor health kills small business: illness and microenterprises in South Africa.

PubMed

Chao, Li-Wei; Pauly, Mark; Szrek, Helena; Pereira, Nuno Sousa; Bundred, Frances; Cross, Catherine; Gow, Jeff

2007-01-01

Small businesses contribute almost 50 percent of total employment and 30 percent of gross domestic product in South Africa, but the impact of poor health and AIDS on these businesses is poorly documented. Using three waves of longitudinal data from predominantly African neighborhoods in peri-urban Durban, South Africa, this project investigates the connections between the health of the owner of a micro- and small enterprise (MSE) and the MSE's growth, survival, or exit. The results show that poor baseline health and declines in health over time are both significantly associated with subsequent business closure.

Attitudes of Undergraduate Business Students toward Sustainability Issues

ERIC Educational Resources Information Center

Eagle, Lynne; Low, David; Case, Peter; Vandommele, Lisa

2015-01-01

Purpose: This paper aims to report on findings from the first phase of a longitudinal study of undergraduate business students' attitudes, beliefs and perceptions concerning sustainability issues. Design/methodology/approach: To improve understanding of the potential effects of changes in the curriculum, business students enrolled during the…

Comparison of the use of a notched wedge joint vs. traditional butt joints in Connecticut : phase 1 report.

DOT National Transportation Integrated Search

2008-05-14

Performance of Hot Mix Asphalt (HMA) longitudinal joints have been an : item of increasing scrutiny in Connecticut. The traditional butt joint : has typically been the method used in Connecticut. These joints have : been reportedly opening up creatin...

Shear waves in vegetal tissues at ultrasonic frequencies

NASA Astrophysics Data System (ADS)

Fariñas, M. D.; Sancho-Knapik, D.; Peguero-Pina, J. J.; Gil-Pelegrín, E.; Gómez Álvarez-Arenas, T. E.

2013-03-01

Shear waves are investigated in leaves of two plant species using air-coupled ultrasound. Magnitude and phase spectra of the transmission coefficient around the first two orders of the thickness resonances (normal and oblique incidence) have been measured. A bilayer acoustic model for plant leaves (comprising the palisade parenchyma and the spongy mesophyll) is proposed to extract, from measured spectra, properties of these tissues like: velocity and attenuation of longitudinal and shear waves and hence Young modulus, rigidity modulus, and Poisson's ratio. Elastic moduli values are typical of cellular solids and both, shear and longitudinal waves exhibit classical viscoelastic losses. Influence of leaf water content is also analyzed.

Phase transition of charged-AdS black holes and quasinormal modes: A time domain analysis

NASA Astrophysics Data System (ADS)

Chabab, M.; El Moumni, H.; Iraoui, S.; Masmar, K.

2017-10-01

In this work, we investigate the time evolution of a massless scalar perturbation around small and large RN-AdS4 black holes for the purpose of probing the thermodynamic phase transition. We show that below the critical point the scalar perturbation decays faster with increasing of the black hole size, both for small and large black hole phases. Our analysis of the time profile of quasinormal mode reveals a sharp distinction between the behaviors of both phases, providing a reliable tool to probe the black hole phase transition. However at the critical point P=Pc, as the black hole size extends, we note that the damping time increases and the perturbation decays faster, the oscillation frequencies raise either in small and large black hole phase. In this case the time evolution approach fails to track the AdS4 black hole phase.

Dynamics of multiple resistance mechanisms in plasma DNA during EGFR-targeted therapies in non-small cell lung cancer.

PubMed

Tsui, Dana Wai Yi; Murtaza, Muhammed; Wong, Alvin Seng Cheong; Rueda, Oscar M; Smith, Christopher G; Chandrananda, Dineika; Soo, Ross A; Lim, Hong Liang; Goh, Boon Cher; Caldas, Carlos; Forshew, Tim; Gale, Davina; Liu, Wei; Morris, James; Marass, Francesco; Eisen, Tim; Chin, Tan Min; Rosenfeld, Nitzan

2018-06-01

Tumour heterogeneity leads to the development of multiple resistance mechanisms during targeted therapies. Identifying the dominant driver(s) is critical for treatment decision. We studied the relative dynamics of multiple oncogenic drivers in longitudinal plasma of 50 EGFR -mutant non-small-cell lung cancer patients receiving gefitinib and hydroxychloroquine. We performed digital PCR and targeted sequencing on samples from all patients and shallow whole-genome sequencing on samples from three patients who underwent histological transformation to small-cell lung cancer. In 43 patients with known EGFR mutations from tumour, we identified them accurately in plasma of 41 patients (95%, 41/43). We also found additional mutations, including EGFR T790M (31/50, 62%), TP53 (23/50, 46%), PIK3CA (7/50, 14%) and PTEN (4/50, 8%). Patients with both TP53 and EGFR mutations before treatment had worse overall survival than those with only EGFR Patients who progressed without T790M had worse PFS during TKI continuation and developed alternative alterations, including small-cell lung cancer-associated copy number changes and TP53 mutations, that tracked subsequent treatment responses. Longitudinal plasma analysis can help identify dominant resistance mechanisms, including non-druggable genetic information that may guide clinical management. © 2018 The Authors. Published under the terms of the CC BY 4.0 license.

Modeling Physical Processes at the Nanoscale—Insight into Self-Organization of Small Systems (abstract)

NASA Astrophysics Data System (ADS)

Proykova, Ana

2009-04-01

Essential contributions have been made in the field of finite-size systems of ingredients interacting with potentials of various ranges. Theoretical simulations have revealed peculiar size effects on stability, ground state structure, phases, and phase transformation of systems confined in space and time. Models developed in the field of pure physics (atomic and molecular clusters) have been extended and successfully transferred to finite-size systems that seem very different—small-scale financial markets, autoimmune reactions, and social group reactions to advertisements. The models show that small-scale markets diverge unexpectedly fast as a result of small fluctuations; autoimmune reactions are sequences of two discontinuous phase transitions; and social groups possess critical behavior (social percolation) under the influence of an external field (advertisement). Some predicted size-dependent properties have been experimentally observed. These findings lead to the hypothesis that restrictions on an object's size determine the object's total internal (configuration) and external (environmental) interactions. Since phases are emergent phenomena produced by self-organization of a large number of particles, the occurrence of a phase in a system containing a small number of ingredients is remarkable.

Theory and Simulation of Gain-Guided Noncollinear Modes in Chirped Quasi-Phase-Matched Optical Parametric Amplifiers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Charbonneau-Lefort, Mathieu; Afeyan, Bedros; Fejer, Martin

Chirped quasi-phase-matched (QPM) gratings offer essentially constant gain over wide bandwidths, making them promising candidates for short-pulse optical parametric amplifiers. However, experiments have shown that high-gain non-collinear processes exist in spite of the dephasing caused by the non-uniformity of the QPM grating and compete with the desired collinear broadband gain of the amplifier. In this paper, these non-collinear gain-guided modes are investigated numerically and analytically in a model that includes longitudinal non-uniformity of the phase-matching profile, lateral localization of the pump beam and non-collinear propagation of the interacting waves.

Self-sustained oscillations of a sinusoidally-deformed plate

NASA Astrophysics Data System (ADS)

Muriel, Diego F.; Cowen, Edwin A.

2015-11-01

Motivated by energy harvesting, the oscillatory motion of a deformed elastic material with aspect ratio Length/Width=2, immerse in an incompressible flow is studied experimentally. To induce the wave-like deformation a polycarbonate sheet is placed under longitudinal compression with external forcing provided by equispaced tension lines anchored in a frame. No additional constrains are placed in the material. Based on quantitative image-based edge detection, ADV, and PIV measurements, we document the existence of three natural states of motion. Bellow a critical velocity, a stable state presents a sinusoidal-like deformation with weak small perturbations. Above a critical velocity, instability appears in the form of a traveling wave with predictable dominant frequency accompanied by higher-order harmonics. As the flow velocity increases the instability converges faster to its limit cycle in the phase plane (e.g., vertical velocity and position), until the stable oscillatory mode transitions to chaos showing a broad energy spectrum and unstable limit cycle. The underlying objective is to induce the onset of the instability at lower critical velocities for higher bending rigidities, promoting possible energy extraction and increasing the range at which stable oscillations appear.

A Saturnian cam current system driven by asymmetric thermospheric heating

NASA Astrophysics Data System (ADS)

Smith, C. G. A.

2011-02-01

We show that asymmetric heating of Saturn's thermosphere can drive a current system consistent with the magnetospheric ‘cam’ proposed by Espinosa, Southwood & Dougherty. A geometrically simple heating distribution is imposed on the Northern hemisphere of a simplified three-dimensional global circulation model of Saturn's thermosphere. Currents driven by the resulting winds are calculated using a globally averaged ionosphere model. Using a simple assumption about how divergences in these currents close by flowing along dipolar field lines between the Northern and Southern hemispheres, we estimate the magnetic field perturbations in the equatorial plane and show that they are broadly consistent with the proposed cam fields, showing a roughly uniform field implying radial and azimuthal components in quadrature. We also identify a small longitudinal phase drift in the cam current with radial distance as a characteristic of a thermosphere-driven current system. However, at present our model does not produce magnetic field perturbations of the required magnitude, falling short by a factor of ˜100, a discrepancy that may be a consequence of an incomplete model of the ionospheric conductance.

Ego-resiliency development from late adolescence to emerging adulthood: A ten-year longitudinal study.

PubMed

Alessandri, Guido; Eisenberg, Nancy; Vecchione, Michele; Caprara, Gian Vittorio; Milioni, Michela

2016-07-01

This study examined the development of ego-resiliency from late adolescence to emerging adulthood, using a 10-year cohort-sequential design. Participants were 335 Italian adolescents (173 females and 162 males), living, at the time of the study, in Genzano, a small city near to Rome. Latent growth curve analyses indicated that the developmental trajectory of ego-resiliency from 15 to 25 years is adequately described by a piecewise model that included separate growth profiles corresponding to different developmental stages. Essentially, ego-resiliency remained remarkably stable until the end of high school, and then encountered a phase of relative increase. Moreover, the trajectory of ego-resiliency from ages 15 to 19 was predicted by self-efficacy beliefs in managing negative emotions, and the trajectory from age 19 to 25 was predicted by experienced familial support and self-efficacy beliefs in expressing positive emotions at age 15. Experienced stressful life events also accounted for individuals' deviation from the typical ego-resiliency trajectory. Copyright © 2016 The Foundation for Professionals in Services for Adolescents. Published by Elsevier Ltd. All rights reserved.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sadovskii, V. M., E-mail: sadov@icm.krasn.ru; Sadovskaya, O. V., E-mail: o-sadov@icm.krasn.ru

Based on the generalized rheological method, the mathematical model describing small deformations of a single-phase porous medium without regard to the effects of a fluid or gas in pores is constructed. The change in resistance of a material to the external mechanical impacts at the moment of pore collapse is taken into account by means of the von Mises–Schleicher strength condition. In order to consider irreversible deformations, alongside with the classical yield conditions by von Mises and Tresca– Saint-Venant, the special condition modeling the plastic loss of stability of a porous skeleton is used. The random nature of the poremore » size distribution is taken into account. It is shown that the proposed mathematical model satisfies the principles of thermodynamics of irreversible processes. Phenomenological parameters of the model are determined on the basis of the approximate calculation of the problem on quasi-static loading of a cubic periodicity cell with spherical voids. In the framework of the obtained model, the process of propagation of plane longitudinal waves of the compression in a homogenous porous medium, accompanied by the plastic deformation of a skeleton and the collapse of pores, is analyzed.« less

Full-wave and ray-based modeling of cross-beam energy transfer between laser beams with distributed phase plates and polarization smoothing

DOE PAGES

Follett, R. K.; Edgell, D. H.; Froula, D. H.; ...

2017-10-20

Radiation-hydrodynamic simulations of inertial confinement fusion (ICF) experiments rely on ray-based cross-beam energy transfer (CBET) models to calculate laser energy deposition. The ray-based models assume locally plane-wave laser beams and polarization averaged incoherence between laser speckles for beams with polarization smoothing. The impact of beam speckle and polarization smoothing on crossbeam energy transfer (CBET) are studied using the 3-D wave-based laser-plasma-interaction code LPSE. The results indicate that ray-based models under predict CBET when the assumption of spatially averaged longitudinal incoherence across the CBET interaction region is violated. A model for CBET between linearly-polarized speckled beams is presented that uses raymore » tracing to solve for the real speckle pattern of the unperturbed laser beams within the eikonal approximation and gives excellent agreement with the wavebased calculations. Lastly, OMEGA-scale 2-D LPSE calculations using ICF relevant plasma conditions suggest that the impact of beam speckle on laser absorption calculations in ICF implosions is small (< 1%).« less

Full-wave and ray-based modeling of cross-beam energy transfer between laser beams with distributed phase plates and polarization smoothing

DOE Office of Scientific and Technical Information (OSTI.GOV)

Follett, R. K.; Edgell, D. H.; Froula, D. H.

Radiation-hydrodynamic simulations of inertial confinement fusion (ICF) experiments rely on ray-based cross-beam energy transfer (CBET) models to calculate laser energy deposition. The ray-based models assume locally plane-wave laser beams and polarization averaged incoherence between laser speckles for beams with polarization smoothing. The impact of beam speckle and polarization smoothing on crossbeam energy transfer (CBET) are studied using the 3-D wave-based laser-plasma-interaction code LPSE. The results indicate that ray-based models under predict CBET when the assumption of spatially averaged longitudinal incoherence across the CBET interaction region is violated. A model for CBET between linearly-polarized speckled beams is presented that uses raymore » tracing to solve for the real speckle pattern of the unperturbed laser beams within the eikonal approximation and gives excellent agreement with the wavebased calculations. Lastly, OMEGA-scale 2-D LPSE calculations using ICF relevant plasma conditions suggest that the impact of beam speckle on laser absorption calculations in ICF implosions is small (< 1%).« less

Bucket shaking stops bunch dancing in Tevatron

DOE Office of Scientific and Technical Information (OSTI.GOV)

Burov, A.; Tan, C.Y.; /Fermilab

2011-03-01

Bunches in Tevatron are known to be longitudinally unstable: their collective oscillations, also called dancing bunches, persist without any signs of decay. Typically, a damper is used to stop these oscillations, but recently, it was theoretically predicted that the oscillations can be stabilized by means of small bucket shaking. Dedicated measurements in Tevatron have shown that this method does stop the dancing. According to predictions of Refs. [2,3], the flattening of the bunch distribution at low amplitudes should make the bunch more stable against LLD. An experiment has been devised to flatten the distribution by modulating the RF phase atmore » the low-amplitude synchrotron frequency for a few degrees of amplitude. These beam studies show that stabilisation really happens. After several consecutive shakings, the dancing disappears and the resulting bunch profile becomes smoother at the top. Although not shown in this report, sometimes a little divot forms at the centre of the distribution. These experiments confirm that resonant RF shaking flattens the bunch distribution at low amplitudes, and the dancing stops.« less

Generation of ultra-long pure magnetization needle and multiple spots by phase modulated doughnut Gaussian beam

NASA Astrophysics Data System (ADS)

Udhayakumar, M.; Prabakaran, K.; Rajesh, K. B.; Jaroszewicz, Z.; Belafhal, Abdelmajid; Velauthapillai, Dhayalan

2018-06-01

Based on vector diffraction theory and inverse Faraday effect (IFE), the light induced magnetization distribution of a tightly focused azimuthally polarized doughnut Gaussian beam superimposed with a helical phase and modulated by an optimized multi belt complex phase filter (MBCPF) is analysed numerically. It is noted that by adjusting the radii of different rings of the complex phase filter, one can achieve many novel magnetization focal distribution such as sub wavelength scale (0.29λ) and super long (52.2λ) longitudinal magnetic probe suitable for all optical magnetic recording and the formation of multiple magnetization chain with four, six and eight sub-wavelength spherical magnetization spots suitable for multiple trapping of magnetic particles are achieved.

Longitudinal conductivity in strong magnetic field in perturbative QCD: Complete leading order

NASA Astrophysics Data System (ADS)

Hattori, Koichi; Li, Shiyong; Satow, Daisuke; Yee, Ho-Ung

2017-04-01

We compute the longitudinal electrical conductivity in the presence of a strong background magnetic field in complete leading order of perturbative QCD, based on the assumed hierarchy of scales αse B ≪(mq2,T2)≪e B . We formulate an effective kinetic theory of lowest Landau level quarks with the leading order QCD collision term arising from 1-to-2 processes that become possible due to 1 +1 dimensional Landau level kinematics. In the small mq/T ≪1 regime, the longitudinal conductivity behaves as σz z˜e2(e B )T /(αsmq2log (T /mq)) , where the quark mass dependence can be understood from the chiral anomaly with the axial charge relaxation provided by a finite quark mass mq. We also present parametric estimates for the longitudinal and transverse "color conductivities" in the presence of the strong magnetic field, by computing dominant damping rates for quarks and gluons that are responsible for color charge transportation. We observe that the longitudinal color conductivity is enhanced by the strong magnetic field, which implies that the sphaleron transition rate in perturbative QCD is suppressed by the strong magnetic field due to the enhanced Lenz's law in color field dynamics.

Five-Year Longitudinal Bone Evaluations in Individuals With Chronic Complete Spinal Cord Injury

PubMed Central

Garland, Douglas E; Adkins, Rodney H; Stewart, Charles A

2008-01-01

Background/Objectives: Knowledge of spinal cord injury (SCI) bone changes has been derived primarily through cross-sectional studies, many of which are controvertible. Longitudinal studies are sparse, and long-term longitudinal chronic studies are unavailable. The objective of this study was to provide a clearer perception of chronic longitudinal bone variations in people with complete SCI. Methods: Bone status of 31 individuals with chronic, complete SCI was assessed twice using dual-energy x-ray absorptiometry at an average interval of 5.06 ± 0.9 years. Because the sample of women was small (4), the primary analyses of change and comparisons of those with paraplegia vs tetraplegia were confined to the male participants. Results: Spine Z-scores showed a significant increase (P < 0.0001). The average Z-scores, initial and follow-up, were within the normal range. Hip Z-scores also showed a significant increase (P < 0.0001), and hip bone mineral density (BMD) increased in 48% of the participants. Knee BMD and lower extremity total bone mineral showed significant decreases (P < 0.003 and P < 0.02, respectively), but increases were seen in 33% and 26% at the respective sites. Individuals with tetraplegia had significantly lower values across all regions (P < 0.0001), and changes were significantly different compared with paraplegia (P < 0.0001). Bone values and changes in men vs women, despite the small sample of women, showed highly significant differences (P < 0.003–0.002). Conclusion: Chronic effects of complete SCI do not exclusively result in continued loss of BMD or a static state of lowered BMD; gain in BMD may occur. The nature and magnitude of the effects of complete SCI on BMD vary by site, with sex and level of injury, which has implications for treatment and its assessment. PMID:19086712

Correlated diffusion of colloidal particles near a liquid-liquid interface.

PubMed

Zhang, Wei; Chen, Song; Li, Na; Zhang, Jia Zheng; Chen, Wei

2014-01-01

Optical microscopy and multi-particle tracking are used to investigate the cross-correlated diffusion of quasi two-dimensional colloidal particles near an oil-water interface. The behaviors of the correlated diffusion along longitudinal and transverse direction are asymmetric. It is shown that the characteristic length for longitudinal and transverse correlated diffusion are particle diameter d and the distance z from particle center to the interface, respectively, for large particle separation z. The longitudinal and transverse correlated diffusion coefficient D||(r) and D[perpendicular](r) are independent of the colloidal area fraction n when n < 0.3, which indicates that the hydrodynamic interactions(HIs) among the particles are dominated by HIs through the surrounding fluid for small n. For high area fraction n > 0.4 the power law exponent for the spatial decay of [Formula: see text] begins to decrease, which suggests the HIs are more contributed from the 2D particle monolayer self for large n.

Can the Southern annular mode influence the Korean summer monsoon rainfall?

NASA Astrophysics Data System (ADS)

Prabhu, Amita; Kripalani, Ramesh; Oh, Jaiho; Preethi, Bhaskar

2017-05-01

We demonstrate that a large-scale longitudinally symmetric global phenomenon in the Southern Hemisphere sub-polar region can transmit its influence over a remote local region of the Northern Hemisphere traveling more than 100° of latitudes (from 70°S to 40°N). This is illustrated by examining the relationship between the Southern Annular Mode (SAM) and the Korean Monsoon Rainfall (KMR) based on the data period 1983-2013. Results reveal that the May-June SAM (MJSAM) has a significant in-phase relationship with the subsequent KMR. A positive MJSAM is favorable for the summer monsoon rainfall over the Korean peninsula. The impact is relayed through the central Pacific Ocean. When a negative phase of MJSAM occurs, it gives rise to an anomalous meridional circulation in a longitudinally locked air-sea coupled system over the central Pacific that propagates from sub-polar to equatorial latitudes and is associated with the central Pacific warming. The ascending motion over the central Pacific descends over the Korean peninsula during peak-boreal summer resulting in weakening of monsoon rainfall. The opposite features prevail during a positive phase of SAM. Thus, the extreme modes of MJSAM could possibly serve as a predictor for ensuing Korean summer monsoon rainfall.

Sleepless night, the moon is bright: longitudinal study of lunar phase and sleep.

PubMed

Röösli, Martin; Jüni, Peter; Braun-Fahrländer, Charlotte; Brinkhof, Martin W G; Low, Nicola; Egger, Matthias

2006-06-01

Popular belief holds that the lunar cycle affects human physiology, behaviour and health. We examined the influence of moon phase on sleep duration in a secondary analysis of a feasibility study of mobile telephone base stations and sleep quality. We studied 31 volunteers (18 women and 13 men, mean age 50 years) from a suburban area of Switzerland longitudinally over 6 weeks, including two full moons. Subjective sleep duration was calculated from sleep diary data. Data were analysed using multiple linear regression models with random effects. Mean sleep duration was 6 h 49 min. Subjective sleep duration varied with the lunar cycle, from 6 h 41 min at full moon to 7 h 00 min at new moon (P < 0.001). Average sleep duration was shortened by 68 min during the week compared with weekends (P < 0.001). Men slept 17 min longer than women (P < 0.001) and sleep duration decreased with age (P < 0.001). There was also evidence that rating of fatigue in the morning was associated with moon phase, with more tiredness (P = 0.027) at full moon. The study was designed for other purposes and the association between lunar cycle and sleep duration will need to be confirmed in further studies.

Feasibility of generating an artificial burst in a turbulent boundary layer, phase 2

NASA Technical Reports Server (NTRS)

Gad-El-hak, Mohamed

1989-01-01

Various drag accounts for about half of the total drag on commercial aircraft at subsonic cruise conditions. Two avenues are available to achieve drag reduction: either laminar flow control or turbulence manipulation. The present research deals with the latter approach. The primary objective of Phase 2 research was to investigate experimentally the feasibility of substantially reducing the skin-friction drag in a turbulent boundary layer. The method combines the beneficial effects of suction and a longitudinally ribbed surface. At a sufficiently large spanwise separation, the streamwise grooves act as a nucleation site causing a focusing of low-speed streaks over the peaks. Suction is then applied intermittently through longitudinal slots located at selected locations along those peaks to obliterate the low-speed regions and to prevent bursting. Phase 2 research was divided into two tasks. In the first, selective suction from a single streamwise slot was used to eliminate either a single burst-like event or a periodic train of artificially generated bursts in laminar and turbulent boundary layers that develop on a flat plate towed in a water channel. The results indicate that equivalent values of the suction coefficient as low as 0.0006 were sufficient to eliminate the artificially generated bursts in a laminar boundary layer.

Metabolome progression during early gut microbial colonization of gnotobiotic mice

PubMed Central

Marcobal, Angela; Yusufaly, Tahir; Higginbottom, Steven; Snyder, Michael; Sonnenburg, Justin L.; Mias, George I.

2015-01-01

The microbiome has been implicated directly in host health, especially host metabolic processes and development of immune responses. These are particularly important in infants where the gut first begins being colonized, and such processes may be modeled in mice. In this investigation we follow longitudinally the urine metabolome of ex-germ-free mice, which are colonized with two bacterial species, Bacteroides thetaiotaomicron and Bifidobacterium longum. High-throughput mass spectrometry profiling of urine samples revealed dynamic changes in the metabolome makeup, associated with the gut bacterial colonization, enabled by our adaptation of non-linear time-series analysis to urine metabolomics data. Results demonstrate both gradual and punctuated changes in metabolite production and that early colonization events profoundly impact the nature of small molecules circulating in the host. The identified small molecules are implicated in amino acid and carbohydrate metabolic processes, and offer insights into the dynamic changes occurring during the colonization process, using high-throughput longitudinal methodology. PMID:26118551

Acculturation and dietary change among Chinese immigrant women in the United States

PubMed Central

Tseng, Marilyn; Wright, David J.; Fang, Carolyn Y

2014-01-01

Background US Chinese immigrants undergo a transition to increased chronic disease risk commonly attributed to acculturative and dietary changes. Longitudinal data to confirm this are lacking. Methods We examined acculturation and diet over time in 312 Chinese immigrant women in Philadelphia, recruited October 2005 to April 2008 and followed with interviews and dietary recalls until April 2010. Associations were modeled using generalized estimating equations to account for repeated measures over time. Results Increasing length of US residence was associated with a small (~1%/year) but significant increase in acculturation score (p<0.0001), which in turn was significantly associated with increased energy density of the diet, percent of energy from fat, and sugar intake, and lower dietary moderation score. Discussion These findings provide longitudinal evidence that acculturation increases with length of US residence and is accompanied by dietary changes. However, the changes were small enough that their health impact is unclear. Factors besides acculturation that affect immigrant health and that affect the acculturation trajectory itself warrant investigation. PMID:25281323

Absorption, scattering, and radiation force efficiencies in the longitudinal wave scattering by a small viscoelastic particle in an isotropic solid.

PubMed

Lopes, J H; Leão-Neto, J P; Silva, G T

2017-11-01

Analytical expressions of the absorption, scattering, and elastic radiation force efficiency factors are derived for the longitudinal plane wave scattering by a small viscoelastic particle in a lossless solid matrix. The particle is assumed to be much smaller than the incident wavelength, i.e., the so-called long-wavelength (Rayleigh) approximation. The efficiencies are dimensionless quantities that represent the absorbed and scattering powers and the elastic radiation force on the particle. In the quadrupole approximation, they are expressed in terms of contrast functions (bulk and shear moduli, and density) between the particle and solid matrix. The results for a high-density polyethylene particle embedded in an aluminum matrix agree with those obtained with the partial wave expansion method. Additionally, the connection between the elastic radiation force and forward scattering function is established through the optical theorem. The present results should be useful for ultrasound characterization of particulate composites, and the development of implanted devices activated by radiation force.

Auto-ignition of methane-air mixtures flowing along an array of thin catalytic plates

NASA Astrophysics Data System (ADS)

Treviño, C.

2010-12-01

In this paper, the heterogeneous ignition of a methane-air mixture flowing along an infinite array of catalytic parallel plates has been studied by inclusion of gas expansion effects and the finite heat conduction on the plates. The system of equations considers the full compressible Navier-Stokes equations coupled with the energy equations of the plates. The gas expansion effects which arise from temperature changes have been considered. The heterogeneous kinetics considers the adsorption and desorption reactions for both reactants. The limits of large and small longitudinal thermal conductance of the plate material are analyzed and the critical conditions for ignition are obtained in closed form. The governing equations are solved numerically using finite differences. The results show that ignition is more easily produced as the longitudinal wall thermal conductance increases, and the effects of the gas expansion on the catalytic ignition process are rather small due to the large value of the activation energy of the desorption reaction of adsorbed oxygen atoms.

Population Change, Community Viability, and Migration Intentions in Selected Utah Communities. Research Report 51.

ERIC Educational Resources Information Center

Kim, Yun; And Others

The first phase of a longitudinal research project, "Assessing Rural Communities' Viability and Associated Factors Under Conditions of Population Change," was conducted in 1975 in eight Utah communities (Panguitch, Richfield, Salina, Delta, Moab, Duchesne, Roosevelt, and Vernal) to provide useful information for planners, researchers,…

A Consideration of Factors Accounting for Goal Effectiveness: A Longitudinal Study.

ERIC Educational Resources Information Center

Stewart, James H.

This research paper presents a model of organizational effectiveness based on the open system perspective and tests four hypotheses concerning organizational effectiveness factors. Organizational effectiveness can be defined as the extent to which a social system makes progress toward objectives based on the four phases of organizational…

Are We Preparing or Training Teachers? Developing Professional Judgment in and beyond Teacher Preparation Programs

ERIC Educational Resources Information Center

Scales, Roya Q.; Wolsey, Thomas DeVere; Lenski, Susan; Smetana, Linda; Yoder, Karen K.; Dobler, Elizabeth; Grisham, Dana L.; Young, Janet R.

2018-01-01

This three phase longitudinal multiple-case study, framed by positioning theory, investigated how four novice teachers learned to use professional judgment in their literacy instruction. Data sources from coursework, student teaching, and novice teaching were included. Interviews, observations, researchers' observational notes, and school and…

A Dialogic Construction of Ethical Standards for the Teaching Profession

ERIC Educational Resources Information Center

Smith, Deirdre Mary

2013-01-01

In Ontario, Canada, both the educational community and the public, which is understood to include parents, students and citizens of the province, participated in a multi-phased, longitudinal, dialogic inquiry to develop a set of ethical standards for the teaching profession. Collective discovery methods, syntheses, and validation of ethical…

Self-Action of Second Harmonic Generation and Longitudinal Temperature Gradient in Nonlinear-Optical Crystals

NASA Astrophysics Data System (ADS)

Baranov, A. I.; Konyashkin, A. V.; Ryabushkin, O. A.

2015-09-01

Model of second harmonic generation with thermal self-action was developed. Second harmonic generation temperature phase matching curves were measured and calculated for periodically polled lithium niobate crystal. Both experimental and calculated data show asymmetrical shift of temperature tuning curves with pump power.

The Effect of School Inspections on School Improvement

ERIC Educational Resources Information Center

Gaertner, Holger; Wurster, Sebastian; Pant, Hans Anand

2014-01-01

This study uses a school-level longitudinal control-group design to examine how teachers and principals of inspected versus uninspected schools perceive school improvement at their schools. During the phasing in of school inspections in the states of Berlin and Brandenburg (Germany), both inspected and uninspected schools were surveyed with…

The Development of Teacher Perspectives: Final Report.

ERIC Educational Resources Information Center

Tabachnick, B. Robert; Zeichner, Kenneth M.

This longitudinal study of the development of perspectives toward teaching consists of three major phases: (1) an examination of the impact of the student teaching experience on the development of teacher perspectives; (2) an examination of the continuing development of teacher perspectives during the first year of teaching; and (3) further…

EFFECTS OF TIDAL CURRENT PHASE AT THE JUNCTION OF TWO STRAITS. (R826940)

EPA Science Inventory

Abstract

Estuaries typically have a monotonic increase in salinity from freshwater at the head of the estuary to ocean water at the mouth, creating a consistent direction for the longitudinal baroclinic pressure gradient. However, Mare Island Strait in San Francisco Ba...

Longitudinal growth of head circumference in term symmetric and asymmetric small for gestational age infants.

PubMed

Kaur, Harvinder; Bhalla, A K; Kumar, Praveen

2012-07-01

To study longitudinal growth pattern of head circumference of full-term symmetric and asymmetric small for gestational age (SGA) infants of the two sexes during first year of life. Mixed-longitudinal growth research design. Head circumference amongst full-term 100 symmetric, 100 asymmetric as well as 100 appropriate for gestational age (AGA) infants was measured at birth, 1, 3, 6, 9 and 12 months of age using standardized technique and instrument. The mean head circumference of male symmetric SGA infants measured significantly (p≤0.001) smaller than asymmetric SGA infants while, in female symmetric SGA infants it measured shorter beyond 6 months. As compared to AGA infants, head circumference in symmetric and asymmetric SGA infants measured significantly smaller in size. Growth velocity for head circumference amongst symmetric and asymmetric SGA male infants did not show statistically significant differences. Rate of head circumference growth remained significantly higher amongst female asymmetric SGA infants than the symmetric ones between 3 and 6 months while, a reversal of trend was observed between 9 and 12 months. The better growth attainments for head circumference of male and female asymmetric SGA infants than their symmetric SGA counterparts during first postnatal year of life may be attributed to the continuation of influence of "head sparing" experienced by asymmetric SGA babies during prenatal life. Copyright © 2011 Elsevier Ltd. All rights reserved.

Regulation and dysregulation of esophageal peristalsis by the integrated function of circular and longitudinal muscle layers in health and disease.

PubMed

Mittal, Ravinder K

2016-09-01

Muscularis propria throughout the entire gastrointestinal tract including the esophagus is comprised of circular and longitudinal muscle layers. Based on the studies conducted in the colon and the small intestine, for more than a century, it has been debated whether the two muscle layers contract synchronously or reciprocally during the ascending contraction and descending relaxation of the peristaltic reflex. Recent studies in the esophagus and colon prove that the two muscle layers indeed contract and relax together in almost perfect synchrony during ascending contraction and descending relaxation of the peristaltic reflex, respectively. Studies in patients with various types of esophageal motor disorders reveal temporal disassociation between the circular and longitudinal muscle layers. We suggest that the discoordination between the two muscle layers plays a role in the genesis of esophageal symptoms, i.e., dysphagia and esophageal pain. Certain pathologies may selectively target one and not the other muscle layer, e.g., in eosinophilic esophagitis there is a selective dysfunction of the longitudinal muscle layer. In achalasia esophagus, swallows are accompanied by the strong contraction of the longitudinal muscle without circular muscle contraction. The possibility that the discoordination between two muscle layers plays a role in the genesis of esophageal symptoms, i.e., dysphagia and esophageal pain are discussed. The purpose of this review is to summarize the regulation and dysregulation of peristalsis by the coordinated and discoordinated function of circular and longitudinal muscle layers in health and diseased states.

Regulation and dysregulation of esophageal peristalsis by the integrated function of circular and longitudinal muscle layers in health and disease

PubMed Central

2016-01-01

Muscularis propria throughout the entire gastrointestinal tract including the esophagus is comprised of circular and longitudinal muscle layers. Based on the studies conducted in the colon and the small intestine, for more than a century, it has been debated whether the two muscle layers contract synchronously or reciprocally during the ascending contraction and descending relaxation of the peristaltic reflex. Recent studies in the esophagus and colon prove that the two muscle layers indeed contract and relax together in almost perfect synchrony during ascending contraction and descending relaxation of the peristaltic reflex, respectively. Studies in patients with various types of esophageal motor disorders reveal temporal disassociation between the circular and longitudinal muscle layers. We suggest that the discoordination between the two muscle layers plays a role in the genesis of esophageal symptoms, i.e., dysphagia and esophageal pain. Certain pathologies may selectively target one and not the other muscle layer, e.g., in eosinophilic esophagitis there is a selective dysfunction of the longitudinal muscle layer. In achalasia esophagus, swallows are accompanied by the strong contraction of the longitudinal muscle without circular muscle contraction. The possibility that the discoordination between two muscle layers plays a role in the genesis of esophageal symptoms, i.e., dysphagia and esophageal pain are discussed. The purpose of this review is to summarize the regulation and dysregulation of peristalsis by the coordinated and discoordinated function of circular and longitudinal muscle layers in health and diseased states. PMID:27445346

Longitudinal Brain Magnetic Resonance Imaging CO2 Stress Testing in Individual Adolescent Sports-Related Concussion Patients: A Pilot Study.

PubMed

Mutch, W Alan C; Ellis, Michael J; Ryner, Lawrence N; Morissette, Marc P; Pries, Philip J; Dufault, Brenden; Essig, Marco; Mikulis, David J; Duffin, James; Fisher, Joseph A

2016-01-01

Advanced neuroimaging studies in concussion have been limited to detecting group differences between concussion patients and healthy controls. In this small pilot study, we used brain magnetic resonance imaging (MRI) CO2 stress testing to longitudinally assess cerebrovascular responsiveness (CVR) in individual sports-related concussion (SRC) patients. Six SRC patients (three males and three females; mean age = 15.7, range = 15-17 years) underwent longitudinal brain MRI CO2 stress testing using blood oxygen level-dependent (BOLD) MRI and model-based prospective end-tidal CO2 targeting under isoxic conditions. First-level and second-level comparisons were undertaken using statistical parametric mapping (SPM) to score the scans and compare them to an atlas of 24 healthy control subjects. All tests were well tolerated and without any serious adverse events. Anatomical MRI was normal in all study participants. The CO2 stimulus was consistent between the SRC patients and control subjects and within SRC patients across the longitudinal study. Individual SRC patients demonstrated both quantitative and qualitative patient-specific alterations in CVR (p < 0.005) that correlated strongly with clinical findings, and that persisted beyond clinical recovery. Standardized brain MRI CO2 stress testing is capable of providing a longitudinal assessment of CVR in individual SRC patients. Consequently, larger prospective studies are needed to examine the utility of brain MRI CO2 stress testing as a clinical tool to help guide the evaluation, classification, and longitudinal management of SRC patients.

Evaluation of a Two-Phase Experimental Study of a Small Group ("MultiLit") Reading Intervention for Older Low-Progress Readers

ERIC Educational Resources Information Center

Buckingham, Jennifer; Beaman-Wheldall, Robyn; Wheldall, Kevin

2014-01-01

The study reported here examined the efficacy of a small group (Tier 2 in a three-tier Response to Intervention model) literacy intervention for older low-progress readers (in Years 3-6). This article focuses on the second phase of a two-phase, crossover randomized control trial involving 26 students. In Phase 1, the experimental group (E1)…

A low bioimpedance phase angle predicts a higher mortality and lower nutritional status in chronic dialysis patients

NASA Astrophysics Data System (ADS)

Dumler Md, Francis

2010-04-01

Bioelectrical impedance analysis is an established technique for body composition analysis. The phase angle parameter, an index of body cell mass, tissue hydration, and membrane integrity, makes it suitable for assessing nutritional status and survivability. We evaluated the significance of a low phase angle value on nutritional status and mortality in 285 chronic dialysis patients during a longitudinal prospective observational study. Patients in the lower phase angle tertile had decreased body weight, body mass index, fat free mass, body cell mass, and lower serum albumin concentrations than those in the higher tertile (P<001). In addition, mortality rates were significantly lower (P=0.05) in the highest tertile patients. In conclusion, the phase angle is a useful method for identifying dialysis patients at high risk for malnutrition and increased mortality.

Working in small-scale, homelike dementia care: effects on staff burnout symptoms and job characteristics. A quasi-experimental, longitudinal study

PubMed Central

Zwakhalen, Sandra MG; Hamers, Jan PH; van Rossum, Erik; Ambergen, Ton; Kempen, Gertrudis IJM; Verbeek, Hilde

2018-01-01

Aim This paper reports on a quasi-experimental, longitudinal study on the effects of working in a new type of dementia care facility (i.e. small-scale living facilities) on staff burnout symptoms and job characteristics (job autonomy, social support, physical demands and workload). Methods It is hypothesised that nursing staff working in small-scale facilities experience fewer burnout symptoms, more autonomy and social support, and fewer symptoms of physical demands and workload compared with staff in regular wards. Two types of long-term institutional nursing care settings were included: 28 houses in small-scale living facilities and 21 regular psychogeriatric wards in nursing homes. At baseline and at follow-ups after 6 and 12 months nursing staff were assessed by means of self-report questionnaires. In total, 305 nursing staff members were included in the study, 114 working in small-scale living facilities (intervention group) and 191 in regular wards (control group). Results No overall effects on burnout symptoms were detected. Significantly fewer physical demands and lower workload were experienced by staff working in small-scale living facilities compared with staff in regular wards. They also experienced more job autonomy. No significant effect was found for overall social support in the total group. Conclusions This study suggests positive effects of the work environment on several work characteristics. Organisational climate differs in the two conditions, which might account for our results. This may influence nursing staff well-being and has important implications for nursing home managers and policy makers. Future studies should enhance our understanding of the influence of job characteristics on outcomes. PMID:29805471

Risk factors for headache in the UK military: cross-sectional and longitudinal analyses.

PubMed

Rona, Roberto J; Jones, Margaret; Goodwin, Laura; Hull, Lisa; Wessely, Simon

2013-05-01

To assess the importance of service demographic, mental disorders, and deployment factors on headache severity and prevalence, and to assess the impact of headache on functional impairment. There is no information on prevalence and risk factors of headache in the UK military. Recent US reports suggest that deployment, especially a combat role, is associated with headache. Such an association may have serious consequences on personnel during deployment. A survey was carried out between 2004 and 2006 (phase 1) and again between 2007 and 2009 (phase 2) of randomly selected UK military personnel to study the health consequences of the Iraq and Afghanistan wars. This study is based on those who participated in phase 2 and includes cross-sectional and longitudinal analyses. Headache severity in the last month and functional impairment at phase 2 were the main outcomes. Forty-six percent complained of headache in phase 2, half of whom endorsed moderate or severe headache. Severe headache was strongly associated with probable post-traumatic stress disorder (multinomial odds ratio [MOR] 9.6, 95% confidence interval [CI] 6.4-14.2), psychological distress (MOR 6.15, 95% CI 4.8-7.9), multiple physical symptoms (MOR 18.2, 95% CI 13.4-24.6) and self-reported mild traumatic brain injury (MOR 3.5, 95% CI 1.4-8.6) after adjustment for service demographic factors. Mild headache was also associated with these variables but at a lower level. Moderate and severe headache were associated with functional impairment, but the association was partially explained by mental disorders. Mental ill health was also associated with reporting moderate and severe headache at both phase 1 and phase 2. Deployment and a combat role were not associated with headache. Moderate and severe headache are common in the military and have an impact on functional impairment. They are more strongly associated with mental disorders than with mild traumatic brain injury. © 2013 American Headache Society.

A modulation technique for the measurement of the DC longitudinal Faraday effect

NASA Astrophysics Data System (ADS)

Hunte, Carlos

2018-03-01

A modulation of light technique, using a lock-in amplifier, is described and tested to investigate the longitudinal Faraday effect in isotropic media. The Faraday rotation is measured directly from the lock-in amplifier. The Verdet constant and dispersion of lead-silica SF-59 Schott glass, at room temperature of 25 °C, were determined for varying wavelengths and expressions for their wavelength dependence were determined. The Verdet constant of water is also investigated. The results compare extremely well with other studies. The technique is suited to measure very small Verdet constants and can be easily conducted in an upper-level undergraduate laboratory.

Two flaps and Z-plasty technique for correction of longitudinal ear lobe cleft.

PubMed

Lee, Paik-Kwon; Ju, Hong-Sil; Rhie, Jong-Won; Ahn, Sang-Tae

2005-06-01

Various surgical techniques have been reported for the correction of congenital ear lobe deformities. Our method, the two-flaps-and-Z-plasty technique, for correcting the longitudinal ear lobe cleft is presented. This technique is simple and easy to perform. It enables us to keep the bulkiness of the ear lobe with minimal tissue sacrifice, and to make a shorter operation scar. The small Z-plasty at the free ear lobe margin avoids notching deformity and makes the shape of the ear lobe smoother. The result is satisfactory in terms of matching the contralateral normal ear lobe in shape and symmetry.

Temperature measurements in an ytterbium fiber amplifier up to the mode instability threshold

NASA Astrophysics Data System (ADS)

Beier, F.; Heinzig, M.; Sattler, Bettina; Walbaum, Till; Haarlammert, N.; Schreiber, T.; Eberhardt, R.; Tünnermann, A.

2016-03-01

We report on the measurement of the longitudinal temperature distribution in a fiber amplifier fiber during high power operation. The measurement signal of an optical frequency domain reflectometer is coupled to an ytterbium doped amplifier fiber via a wavelength division multiplexer. The longitudinal temperature distribution was examined for different pump powers with a sub mm resolution. The results show even small temperature variations induced by slight changes of the environmental conditions along the fiber. The mode instability threshold of the fiber under investigation was determined to be 480W and temperatures could be measured overall the measured output power values.

High-power, single-longitudinal-mode terahertz-wave generation pumped by a microchip Nd:YAG laser [Invited].

PubMed

Hayashi, Shin'ichiro; Nawata, Koji; Sakai, Hiroshi; Taira, Takunori; Minamide, Hiroaki; Kawase, Kodo

2012-01-30

We report on the development of a high-peak-power, single-longitudinal-mode and tunable injection-seeded terahertz-wave parametric generator using MgO:LiNbO3, which operates at room temperature. The high peak power (> 120 W) is enough to allow easy detection by commercial and calibrated pyroelectric detectors, and the spectral resolution (< 10 GHz) is the Fourier transform limit of the sub-nanosecond terahertz-wave pulse. The tunability (1.2-2.8 THz) and the small footprint size (A3 paper, 29.7 × 42 cm) are suitable for a variety of applications.

Epidemics with pathogen mutation on small-world networks

NASA Astrophysics Data System (ADS)

Shao, Zhi-Gang; Tan, Zhi-Jie; Zou, Xian-Wu; Jin, Zhun-Zhi

2006-05-01

We study the dynamical behavior of the epidemiological model with pathogen mutation on small-world networks, and discuss the influence of the immunity duration τR, the cross-immunity threshold hthr, and system size N on epidemic dynamics. A decaying oscillation occurs because of the interplay between the immune response and the pathogen mutation. These results have implications for the interpretation of longitudinal epidemiological data on strain abundance, and they will be helpful to assess the threat of highly pathogenic and mutative viruses, such as avian influenza.

On the Longitudinal Morphology of Zonal Irregularity Drift Measured using Networks of GPS Scintillation Monitors

NASA Astrophysics Data System (ADS)

Carrano, C. S.; Groves, K. M.; Valladares, C. E.; Delay, S. H.

2014-12-01

A complete characterization of field-aligned ionospheric irregularities responsible for the scintillation of satellite signals includes not only their spectral properties (power spectral strength, spectral index, anisotropy ratio, and outer-scale) but also their horizontal drift velocity. From a system impacts perspective, the horizontal drift velocity is important in that it dictates the rate of signal fading and also, to an extent, the level of phase fluctuations encountered by the receiver. From a physics perspective, studying the longitudinal morphology of zonal irregularity may lead to an improved understanding of the F region dynamo and regional electrodynamics at low latitudes. The irregularity drift at low latitudes is predominantly zonal and is most commonly measured by cross-correlating observations of satellite signals made by a pair of closely-spaced antennas. The AFRL-SCINDA network operates a small number of VHF spaced-antenna systems at low latitude stations for this purpose. A far greater number of GPS scintillation monitors are operated by AFRL-SCINDA (25-30) and the Low Latitude Ionospheric Sensor Network (35-50), but the receivers are situated too far apart to monitor the drift using cross-correlation techniques. In this paper, we present an alternative approach that leverages the weak scatter scintillation theory (Rino, Radio Sci., 1979) to infer the zonal irregularity drift from single-station GPS measurements of S4, sigma-phi, and the propagation geometry alone. Unlike the spaced-receiver technique, this technique requires assumptions for the height of the scattering layer (which introduces a bias in the drift estimates) and the spectral index of the irregularities (which affects the spread of the drift estimates about the mean). Nevertheless, theory and experiment show that the ratio of sigma-phi to S4 is less sensitive to these parameters than it is to the zonal drift, and hence the zonal drift can be estimated with reasonable accuracy. In this talk, we first validate the technique using spaced VHF-antenna measurements of zonal irregularity drift from the AFRL-SCINDA network. Next, we discuss preliminary results from our investigation into the longitudinal morphology of zonal irregularity drift using the AFRL-SCINDA and LISN networks of GPS scintillation monitors.

Effects of Dai-kenchu-to on spontaneous activity in the mouse small intestine.

PubMed

Kito, Yoshihiko; Suzuki, Hikaru

2006-12-01

The effects of Dai-kenchu-to (DKT), a Chinese medicine, on spontaneous activity of mouse small intestine were investigated. Experiments were carried out with tension recording and intracellular recording. DKT contracted mouse longitudinal smooth muscles in a dose dependent manner (0.1-10 mg/ml). Low concentration of DKT (0.1 mg/ml) did not contract the longitudinal muscles of mouse small intestine. DKT (0.1 mg/ml) inhibited contraction elicited by transmural nerve stimulation (TNS). DKT (1 mg/ml) evoked relaxation before contraction. The initial relaxation was abolished by Nomega-nitro-L-arginine (L-NNA). DKT (10 mg/ml)-induced contraction had two components: a transient rapid contraction and a following slow contraction. Atropine inhibited DKT (1 mg/ml)-induced contraction to about 50% of control. In the presence of atropine, tetrodotoxin (TTX) inhibited the contraction elicited by DKT (1 mg/ml) to about 80%. DKT depolarized the membrane and decreased the amplitude of pacemaker potentials recorded from in situ myenteric interstitial cells of Cajal (ICC-MY) with no alteration to the frequency, duration and maximum rates of rise in the presence of nifedipine and TTX. The same results were obtained in slow waves recorded from circular smooth muscle cells. These results indicate that DKT evoked both contraction and relaxation by releasing acetylcholine, nitric oxide and other excitatory neurotransmitters in mouse small intestine. DKT had no effects on pacemaker mechanisms and electrical coupling between ICC-MY and smooth muscle cells in mouse small intestine. The results also suggest that DKT may contract smooth muscles by depolarizing the membrane directly.

The regional economic impacts of bypasses : a longitudinal study incorporating spatial panel econometrics and multilevel modeling.

DOT National Transportation Integrated Search

2011-09-01

This paper will describe an integrated approach to documenting and quantifying the impacts of bypasses : on small communities, with a focus on what economic impacts, if any, occur, and how these impacts : change over time. Two similarly sized communi...

Unconventional superconductivity in magic-angle graphene superlattices.

PubMed

Cao, Yuan; Fatemi, Valla; Fang, Shiang; Watanabe, Kenji; Taniguchi, Takashi; Kaxiras, Efthimios; Jarillo-Herrero, Pablo

2018-04-05

The behaviour of strongly correlated materials, and in particular unconventional superconductors, has been studied extensively for decades, but is still not well understood. This lack of theoretical understanding has motivated the development of experimental techniques for studying such behaviour, such as using ultracold atom lattices to simulate quantum materials. Here we report the realization of intrinsic unconventional superconductivity-which cannot be explained by weak electron-phonon interactions-in a two-dimensional superlattice created by stacking two sheets of graphene that are twisted relative to each other by a small angle. For twist angles of about 1.1°-the first 'magic' angle-the electronic band structure of this 'twisted bilayer graphene' exhibits flat bands near zero Fermi energy, resulting in correlated insulating states at half-filling. Upon electrostatic doping of the material away from these correlated insulating states, we observe tunable zero-resistance states with a critical temperature of up to 1.7 kelvin. The temperature-carrier-density phase diagram of twisted bilayer graphene is similar to that of copper oxides (or cuprates), and includes dome-shaped regions that correspond to superconductivity. Moreover, quantum oscillations in the longitudinal resistance of the material indicate the presence of small Fermi surfaces near the correlated insulating states, in analogy with underdoped cuprates. The relatively high superconducting critical temperature of twisted bilayer graphene, given such a small Fermi surface (which corresponds to a carrier density of about 10 11 per square centimetre), puts it among the superconductors with the strongest pairing strength between electrons. Twisted bilayer graphene is a precisely tunable, purely carbon-based, two-dimensional superconductor. It is therefore an ideal material for investigations of strongly correlated phenomena, which could lead to insights into the physics of high-critical-temperature superconductors and quantum spin liquids.

Unconventional superconductivity in magic-angle graphene superlattices

NASA Astrophysics Data System (ADS)

Cao, Yuan; Fatemi, Valla; Fang, Shiang; Watanabe, Kenji; Taniguchi, Takashi; Kaxiras, Efthimios; Jarillo-Herrero, Pablo

2018-04-01

The behaviour of strongly correlated materials, and in particular unconventional superconductors, has been studied extensively for decades, but is still not well understood. This lack of theoretical understanding has motivated the development of experimental techniques for studying such behaviour, such as using ultracold atom lattices to simulate quantum materials. Here we report the realization of intrinsic unconventional superconductivity—which cannot be explained by weak electron–phonon interactions—in a two-dimensional superlattice created by stacking two sheets of graphene that are twisted relative to each other by a small angle. For twist angles of about 1.1°—the first ‘magic’ angle—the electronic band structure of this ‘twisted bilayer graphene’ exhibits flat bands near zero Fermi energy, resulting in correlated insulating states at half-filling. Upon electrostatic doping of the material away from these correlated insulating states, we observe tunable zero-resistance states with a critical temperature of up to 1.7 kelvin. The temperature–carrier-density phase diagram of twisted bilayer graphene is similar to that of copper oxides (or cuprates), and includes dome-shaped regions that correspond to superconductivity. Moreover, quantum oscillations in the longitudinal resistance of the material indicate the presence of small Fermi surfaces near the correlated insulating states, in analogy with underdoped cuprates. The relatively high superconducting critical temperature of twisted bilayer graphene, given such a small Fermi surface (which corresponds to a carrier density of about 1011 per square centimetre), puts it among the superconductors with the strongest pairing strength between electrons. Twisted bilayer graphene is a precisely tunable, purely carbon-based, two-dimensional superconductor. It is therefore an ideal material for investigations of strongly correlated phenomena, which could lead to insights into the physics of high-critical-temperature superconductors and quantum spin liquids.

BIOMASS-FUELED, SMALL-SCALE, INTEGRATED-GASIFIER, GAS-TURBINE POWER PLANT: PROGRESS REPORT ON THE PHASE 2 DEVELOPMENT

EPA Science Inventory

The paper reports the latest efforts to complete development of Phase 2 of a three-phase effort to develop a family of small-scale (1 to 20 MWe) biomass-fueled power plants. The concept envisioned is an air-blown pressurized fluidized-bed gasifier followed by a dry hot gas clean...

Examining unanswered questions about the home environment and childhood obesity disparities using an incremental, mixed-methods, longitudinal study design: The Family Matters study.

PubMed

Berge, Jerica M; Trofholz, Amanda; Tate, Allan D; Beebe, Maureen; Fertig, Angela; Miner, Michael H; Crow, Scott; Culhane-Pera, Kathleen A; Pergament, Shannon; Neumark-Sztainer, Dianne

2017-11-01

There are disparities in the prevalence of childhood obesity for children from low-income and minority households. Mixed-methods studies that examine home environments in an in-depth manner are needed to identify potential mechanisms driving childhood obesity disparities that have not been examined in prior research. The Family Matters study aims to identify risk and protective factors for childhood obesity in low-income and minority households through a two-phased incremental, mixed-methods, and longitudinal approach. Individual, dyadic (i.e., parent/child; siblings), and familial factors that are associated with, or moderate associations with childhood obesity will be examined. Phase I includes in-home observations of diverse families (n=150; 25 each of African American, American Indian, Hispanic/Latino, Hmong, Somali, and White families). In-home observations include: (1) an interactive observational family task; (2) ecological momentary assessment of parent stress, mood, and parenting practices; (3) child and parent accelerometry; (4) three 24-hour child dietary recalls; (5) home food inventory; (6) built environment audit; (7) anthropometry on all family members; (8) an online survey; and (9) a parent interview. Phase I data will be used for analyses and to inform development of a culturally appropriate survey for Phase II. The survey will be administered at two time points to diverse parents (n=1200) of children ages 5-9. The main aim of the current paper is to describe the Family Matters complex study design and protocol and to report Phase I feasibility data for participant recruitment and study completion. Results from this comprehensive study will inform the development of culturally-tailored interventions to reduce childhood obesity disparities. Copyright © 2017 Elsevier Inc. All rights reserved.

A Photometric Model of the Inclined F Ring of Saturn

NASA Astrophysics Data System (ADS)

Scharringhausen, Britt; Nicholson, P. D.

2007-10-01

Hubble Space Telescope (HST) observations of the August 1995 Saturn ring-plane crossing (RPX) by Earth revealed a surprising east-west asymmetry in ring brightness both before and after the RPX (Nicholson et al. 1996). Previous F-ring models (Poulet et al. 2000) used the overall ring brightness near RPX to probe the photometric thickness of the F ring. In the current work, we exploit the fact that the brightness asymmetry is sensitive to the inclination, node, and physical height of the F ring. We use the inclined F-ring orbit of Bosh et al. (2002), and treat the F ring as a longitudinally symmetric "ribbon" of uniform albedo and phase function with a vertical Gaussian distribution of radial optical depth that has a full height at half maximum of 13±7 km and an equivalent depth (i.e. radially-integrated normal optical depth) of 10±4 km. The model reproduces the observed asymmetry in ring brightness immediately after the RPX, when the Earth is on the sunlit side of the main rings. The F ring obscures the east ansa to a greater extent than the west ansa and the sense of the asymmetry then reverses as the Earth passes through the F-ring plane. Before the RPX, the model does not reproduce the small observed asymmetry in ring brightness, suggesting that the dark-side asymmetry is due to longitudinal variations in the F ring rather than blocking effects. The shapes of model radial profiles of ring brightness are a good match to the HST data both before and after the RPX. This work was supported by NASA.

Malalignment and subchondral bone turnover in contralateral knees of overweight/obese women with unilateral osteoarthritis: implications for bilateral disease.

PubMed

Mazzuca, Steven A; Brandt, Kenneth D; Lane, Kathleen A; Chakr, Rafael

2011-11-01

To explore whether the risk of incident tibiofemoral (TF) osteoarthritis (OA) in the radiographically normal contralateral knee of overweight/obese women with unilateral knee OA is mediated by malalignment and/or preceded by increased turnover of subchondral bone. We used data of post hoc analyses from a randomized controlled trial. Cross-sectional analyses evaluated the baseline association between frontal plane alignment and bone turnover in the medial TF compartment in 78 radiographically normal contralateral knees. Longitudinal analyses ascertained whether incident radiographic OA (TF osteophyte formation within 30 months) was associated with malalignment and/or increased bone turnover at baseline. Alignment subcategories (varus/neutral/valgus) were based on the anatomic axis angle. (99m)Tc-methylene diphosphonate uptake in a late-phase bone scan was quantified in regions of interest in the medial tibia (MT) and medial femur (MF) and adjusted for uptake in a reference segment of the ipsilateral tibial shaft (TS). MF and MT uptake in varus contralateral knees was 50-55% greater than in the TS. Adjusted MT uptake in varus contralateral knees was significantly greater than that in neutral and valgus contralateral knees (mean 1.55 versus 1.38 and 1.43, respectively; P < 0.05). Among 69 contralateral knees followed longitudinally, 22 (32%) developed TF OA. Varus angulation was associated with a marginally significant increase in the odds of incident OA (adjusted odds ratio 3.98, P = 0.067). While the small sample size limited our ability to detect statistically significant risk factors, these data suggest that the risk of developing bilateral TF OA in overweight/obese women may be mediated by varus malalignment. Copyright © 2011 by the American College of Rheumatology.

Haplotype-based association analysis of general cognitive ability in Generation Scotland, the English Longitudinal Study of Ageing, and UK Biobank.

PubMed

Howard, David M; Adams, Mark J; Clarke, Toni-Kim; Wigmore, Eleanor M; Zeng, Yanni; Hagenaars, Saskia P; Lyall, Donald M; Thomson, Pippa A; Evans, Kathryn L; Porteous, David J; Nagy, Reka; Hayward, Caroline; Haley, Chris S; Smith, Blair H; Murray, Alison D; Batty, G David; Deary, Ian J; McIntosh, Andrew M

2017-01-01

Cognitive ability is a heritable trait with a polygenic architecture, for which several associated variants have been identified using genotype-based and candidate gene approaches. Haplotype-based analyses are a complementary technique that take phased genotype data into account, and potentially provide greater statistical power to detect lower frequency variants. In the present analysis, three cohort studies (n total = 48,002) were utilised: Generation Scotland: Scottish Family Health Study (GS:SFHS), the English Longitudinal Study of Ageing (ELSA), and the UK Biobank. A genome-wide haplotype-based meta-analysis of cognitive ability was performed, as well as a targeted meta-analysis of several gene coding regions. None of the assessed haplotypes provided evidence of a statistically significant association with cognitive ability in either the individual cohorts or the meta-analysis. Within the meta-analysis, the haplotype with the lowest observed P -value overlapped with the D-amino acid oxidase activator ( DAOA ) gene coding region. This coding region has previously been associated with bipolar disorder, schizophrenia and Alzheimer's disease, which have all been shown to impact upon cognitive ability. Another potentially interesting region highlighted within the current genome-wide association analysis (GS:SFHS: P = 4.09 x 10 -7 ), was the butyrylcholinesterase ( BCHE ) gene coding region. The protein encoded by BCHE has been shown to influence the progression of Alzheimer's disease and its role in cognitive ability merits further investigation. Although no evidence was found for any haplotypes with a statistically significant association with cognitive ability, our results did provide further evidence that the genetic variants contributing to the variance of cognitive ability are likely to be of small effect.

Correlations of phase structure and thermal stability for Alnico 8 alloys

NASA Astrophysics Data System (ADS)

Zhao, J. T.; Sun, Y. L.; Liu, L.; Lee, D.; Liu, Z.; Feng, X. C.; Yan, A. R.

2017-11-01

The correlations of phase structure and thermal stability for Alnico 8 alloys is analyzed by three-step aging at 650 °C, 600 °C and 550 °C gradually in this paper. After three-step aging the a1 phase is a chess-like structure in transverse direction and a bamboo-like structure in longitudinal direction. Meanwhile the magnetic energy product ((BH)m) increases from 9.17 MGOe to 10.59 MGOe, and the remanence temperature coefficient a(RT-180 °C) reduces from -2.31 %%/°C to -1.25 %%/°C. The MPMS and VSM measurements indicate that three-step aging makes the a1 phase be single domain particles and dispersed distribution, which plays an important role in optimizing the thermal stability of Alnico alloys.

Soft x-ray resonant diffraction study of magnetic structure in magnetoelectric Y-type hexaferrite

NASA Astrophysics Data System (ADS)

Ueda, H.; Tanaka, Y.; Wakabayashi, Y.; Kimura, T.

2018-05-01

The effect of magnetic field on the magnetic structure associated with magnetoelectric properties in a Y-type hexaferrite, Ba1.3Sr0.7CoZnFe11AlO22, was investigated by utilizing the soft x-ray resonant diffraction technique. In this hexaferrite, the so-called alternating longitudinal conical phase is stabilized at room temperature and zero magnetic field. Below room temperature, however, this phase is transformed into the so-called transverse conical phase by applying an in-plane magnetic field (≈ 0.3 T). The transverse conical phase persists even after removing the magnetic field. The magnetoelectricity, which is magnetically-induced electric polarization, observed in the hexaferrite is discussed in terms of the temperature-dependent magnetic structure at zero field.

Acoustic Guided Wave Testing of Pipes of Small Diameters

NASA Astrophysics Data System (ADS)

Muravev, V. V.; Muraveva, O. V.; Strizhak, V. A.; Myshkin, Y. V.

2017-10-01

Acoustic path is analyzed and main parameters of guided wave testing are substanti- ated applied to pipes of small diameters. The method is implemented using longitudinal L(0,1) and torsional T(0,1) waves based on electromagnetic-acoustic (EMA) transducers. The method of multiple reflections (MMR) combines echo-through, amplitude-shadow and time-shadow methods. Due to the effect of coherent amplification of echo-pulses from defects the sensitivity to the defects of small sizes at the signal analysis on the far reflections is increased. An oppor- tunity of detection of both local defects (dents, corrosion damages, rolling features, pitting, cracks) and defects extended along the pipe is shown.

Registration Methods for IVUS: Transversal and Longitudinal Transducer Motion Compensation.

PubMed

Talou, Gonzalo D Maso; Blanco, Pablo J; Larrabide, Ignacio; Bezerra, Cristiano Guedes; Lemos, Pedro A; Feijoo, Raul A

2017-04-01

Intravascular ultrasound (IVUS) is a fundamental imaging technique for atherosclerotic plaque assessment, interventionist guidance, and, ultimately, as a tissue characterization tool. The studies acquired by this technique present the spatial description of the vessel during the cardiac cycle. However, the study frames are not properly sorted. As gating methods deal with the cardiac phase classification of the frames, the gated studies lack motion compensation between vessel and catheter. In this study, we develop registration strategies to arrange the vessel data into its rightful spatial sequence. Registration is performed by compensating longitudinal and transversal relative motion between vessel and catheter. Transversal motion is identified through maximum likelihood estimator optimization, while longitudinal motion is estimated by a neighborhood similarity estimator among the study frames. A strongly coupled implementation is proposed to compensate for both motion components at once. Loosely coupled implementations (DLT and DTL) decouple the registration process, resulting in more computationally efficient algorithms in detriment of the size of the set of candidate solutions. The DTL outperforms DLT and coupled implementations in terms of accuracy by a factor of 1.9 and 1.4, respectively. Sensitivity analysis shows that perivascular tissue must be considered to obtain the best registration outcome. Evidences suggest that the method is able to measure axial strain along the vessel wall. The proposed registration sorts the IVUS frames for spatial location, which is crucial for a correct interpretation of the vessel wall kinematics along the cardiac phases.

Virtual photon polarization and dilepton anisotropy in relativistic nucleus-nucleus collisions

NASA Astrophysics Data System (ADS)

Speranza, Enrico; Jaiswal, Amaresh; Friman, Bengt

2018-07-01

The polarization of virtual photons produced in relativistic nucleus-nucleus collisions provides information on the conditions in the emitting medium. In a hydrodynamic framework, the resulting angular anisotropy of the dilepton final state depends on the flow as well as on the transverse momentum and invariant mass of the photon. We illustrate these effects in dilepton production from quark-antiquark annihilation in the QGP phase and π+π- annihilation in the hadronic phase for a static medium in global equilibrium and for a longitudinally expanding system.

Fabrication of computer-generated holograms using femtosecond laser direct writing.

PubMed

Berlich, René; Richter, Daniel; Richardson, Martin; Nolte, Stefan

2016-04-15

We demonstrate a single-step fabrication method for computer-generated holograms based on femtosecond laser direct writing. Therefore, a tightly arranged longitudinal waveguide array is directly inscribed into a transparent material. By tailoring the individual waveguide length, the phase profile of an incident laser beam can be arbitrarily adapted. The approach is verified in common borosilicate glass by inscribing a designed phase hologram, which forms the desired intensity pattern in its far field. The resulting performance is analyzed, and the potential as well as limitations of the method are discussed.

Propagating stress-pulses and wiggling transition revealed in string dynamics

NASA Astrophysics Data System (ADS)

Yao, Zhenwei

2018-02-01

Understanding string dynamics yields insights into the intricate dynamic behaviors of various filamentary thin structures in nature and industry covering multiple length scales. In this work, we investigate the planar dynamics of a flexible string where one end is free and the other end is subject to transverse and longitudinal motions. Under transverse harmonic motion, we reveal the propagating pulse structure in the stress profile over the string, and analyze its role in bringing the system into a chaotic state. For a string where one end is under longitudinal uniform acceleration, we identify the wiggling transition, derive the analytical wiggling solution from the string equations, and present the phase diagram.

Study of the heavy ion bunch compression in CSRm

NASA Astrophysics Data System (ADS)

Yin, Da-Yu; Liu, Yong; Yuan, You-Jing; Yang, Jian-Cheng; Li, Peng; Li, Jie; Chai, Wei-Ping; Sha, Xiao-Ping

2013-05-01

The feasibility of attaining nanosecond pulse length heavy ion beam is studied in the main ring (CSRm) of the Heavy Ion Research Facility in Lanzhou. Such heavy ion beam can be produced by non-adiabatic compression, and it is implemented by a fast rotation in the longitudinal phase space. In this paper, the possible beam parameters during longitudinal bunch compression are studied with the envelope model and Particle in Cell simulation, and the results are compared. The result shows that the short bunch 238U28+ with the pulse duration of about 50 ns at the energy of 200 MeV/u can be obtained which can satisfy the research of high density plasma physics experiment.

Isentropic phase changes in dissociating gases and the method of sound dispersion for the investigation of homogeneous gas reactions with very high speed : Conclusion

NASA Technical Reports Server (NTRS)

Damkohler, Gerhard

1950-01-01

The analytical results of Part I are also applied to sound dispersion by friction and heat conduction, An irreversible change of momentum, energy, and type of particle corresponding to friction, heat conduction, and diffusion effects can appear both in the direction of the sound field and traverse to it. Longitudinal damping, the coupling of longitudinal damping and that due to chemical and physical changes, and coupling of diffusion and compositional changes are treated for a plane sound wave of infinite extent. The same principles are also applied to sound effects in cylindrical tubes. The limitations of the method are discussed in some detail.

Laryngeal flow due to longitudinal sweeping motion of the vocal folds and its contribution to auto-oscillation.

PubMed

Boutin, Henri; Smith, John; Wolfe, Joe

2015-07-01

Analysis of published depth-kymography data [George, de Mul, Qiu, Rakhorst, and Schutte (2008). Phys. Med. Biol. 53, 2667-2675] shows that, for the subject studied, the flow due to the longitudinal sweeping motion of the vocal folds contributes several percent of a typical acoustic flow at the larynx. This sweeping flow is a maximum when the glottis is closed. This observation suggests that assumption of zero laryngeal flow during the closed phase as a criterion when determining parameters in inverse filtering should be used with caution. Further, these data suggest that the swinging motion contributes work to overcome mechanical losses and thus to assist auto-oscillation.

Fiber Laser Development for LISA

NASA Technical Reports Server (NTRS)

Numata, Kenji; Chen, Jeffrey R.

2009-01-01

We have developed a linearly-polarized Ytterbium-doped fiber ring laser with single longitudinal-mode output at 1064nm for LISA and other space applications. Single longitudinal-mode selection was achieved by using a fiber Bragg grating (FBG) and a fiber Fabry-Perot (FFP). The FFP also serves as a frequency-reference within our ring laser. Our laser exhibits comparable low frequency and intensity noise to Non-Planar Ring Oscillator (NPRO). By using a fiber-coupled phase modulator as a frequency actuator, the laser frequency can be electro-optically tuned at a rate of 100kHz. It appears that our fiber ring laser is promising for space applications where robustness of fiber optics is desirable.

Elastic properties of aspirin in its crystalline and glassy phases studied by micro-Brillouin scattering

NASA Astrophysics Data System (ADS)

Ko, Jae-Hyeon; Lee, Kwang-Sei; Ike, Yuji; Kojima, Seiji

2008-11-01

The acoustic waves propagating along the direction perpendicular to the (1 0 0) cleavage plane of aspirin crystal were investigated using micro-Brillouin spectroscopy from which C11, C55 and C66 were obtained. The temperature dependence of the longitudinal acoustic waves could be explained by normal anharmonic lattice models, while the transverse acoustic waves showed an abnormal increase in the hypersonic attenuation at low temperatures indicating their coupling to local remnant dynamics. The sound velocity as well as the attenuation of the longitudinal acoustic waves of glassy aspirin showed a substantial change at ˜235 K confirming a transition from glassy to supercooled liquid state in vitreous aspirin.

KSC SBIR/STTR 2004 Program Year Report

NASA Technical Reports Server (NTRS)

2005-01-01

The Kennedy Space Center Level III SBIR/STTR management staff is under the Technology Transfer Office within the Spaceport Engineering and Technology Directorate. The SBIR and STTR programs provide an opportunity for small high technology companies and research institutions to participate in Government-sponsored research and development (R&D) programs in key technology areas. The SBIR program was established by Congress in 1982 to provide increased opportunities for small businesses to participate in R&D programs, increase employment, and improve U.S. competitiveness. The program's specific objectives are to stimulate U.S. technological innovation, use small businesses to meet Federal research and development needs, increase private sector commercialization of innovations, and foster and encourage participation by socially disadvantaged businesses. Legislation enacted in December 2000 reauthorized the program and strengthened emphasis on pursuing commercial applications of SBIR projects. An SBIR Phase I contract is the opportunity to establish the feasibility and technical merit of a proposed innovation. Selected competitively, the Phase I contract lasts for 6 months and is funded up to $70,000. SBIR Phase II contracts continue the most promising Phase I projects based on scientific! technical merit, expected value to NASA, company capability, and commercial potential. Phase II contracts are usually for a period of 24 months and may not exceed $600,000. NASA usually selects approximately 40 percent of Phase I projects to continue to the Phase II level. Phase III is the process of furthering the development of a product to make it commercially available. The STTR program awards contracts to small business concerns for cooperative R&D with a nonprofit research institution. Research institutions include nonprofit research organizations, Federal laboratories, or universities. The goal of the program established by Congress is to facilitate the transfer of technology developed by a research institution through the entrepreneurship of a small business. The STIR program is smaller in funding than the SBIR program. While the proposal is submitted by the small business concern, at least 30 percent of the funding and work must originate with the research institution. STTR Phase I projects receive up to $100K for a one-year effort, and a Phase II contract receives up to $600K for two years.

Precision Laser Annealing of Focal Plane Arrays

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bender, Daniel A.; DeRose, Christopher; Starbuck, Andrew Lea

2015-09-01

We present results from laser annealing experiments in Si using a passively Q-switched Nd:YAG microlaser. Exposure with laser at fluence values above the damage threshold of commercially available photodiodes results in electrical damage (as measured by an increase in photodiode dark current). We show that increasing the laser fluence to values in excess of the damage threshold can result in annealing of a damage site and a reduction in detector dark current by as much as 100x in some cases. A still further increase in fluence results in irreparable damage. Thus we demonstrate the presence of a laser annealing windowmore » over which performance of damaged detectors can be at least partially reconstituted. Moreover dark current reduction is observed over the entire operating range of the diode indicating that device performance has been improved for all values of reverse bias voltage. Additionally, we will present results of laser annealing in Si waveguides. By exposing a small (<10 um) length of a Si waveguide to an annealing laser pulse, the longitudinal phase of light acquired in propagating through the waveguide can be modified with high precision, <15 milliradian per laser pulse. Phase tuning by 180 degrees is exhibited with multiple exposures to one arm of a Mach-Zehnder interferometer at fluence values below the morphological damage threshold of an etched Si waveguide. No reduction in optical transmission at 1550 nm was found after 220 annealing laser shots. Modeling results for laser annealing in Si are also presented.« less

Dynamic ground-effect measurements on the F-15 STOL and Maneuver Technology Demonstrator (S/MTD) configuration

NASA Technical Reports Server (NTRS)

Kemmerly, Guy T.

1990-01-01

A moving-model ground-effect testing method was used to study the influence of rate-of-descent on the aerodynamic characteristics for the F-15 STOL and Maneuver Technology Demonstrator (S/MTD) configuration for both the approach and roll-out phases of landing. The approach phase was modeled for three rates of descent, and the results were compared to the predictions from the F-15 S/MTD simulation data base (prediction based on data obtained in a wind tunnel with zero rate of descent). This comparison showed significant differences due both to the rate of descent in the moving-model test and to the presence of the ground boundary layer in the wind tunnel test. Relative to the simulation data base predictions, the moving-model test showed substantially less lift increase in ground effect, less nose-down pitching moment, and less increase in drag. These differences became more prominent at the larger thrust vector angles. Over the small range of rates of descent tested using the moving-model technique, the effect of rate of descent on longitudinal aerodynamics was relatively constant. The results of this investigation indicate no safety-of-flight problems with the lower jets vectored up to 80 deg on approach. The results also indicate that this configuration could employ a nozzle concept using lower reverser vector angles up to 110 deg on approach if a no-flare approach procedure were adopted and if inlet reingestion does not pose a problem.

Effect of Schools upon Small Community Growth and Decline.

ERIC Educational Resources Information Center

Voth, Donald E.; Danforth, Diana M.

1981-01-01

Results of a 20-year longitudinal study to determine whether change in the presence or absence of schools and in the number of schools operating in a community could be demonstrated to influence community growth. Available from: Rural Sociological Society, 325 Morgan Hall, University of Tennessee, Knoxville, TN 37916. (NEC)

Fitting Residual Error Structures for Growth Models in SAS PROC MCMC

ERIC Educational Resources Information Center

McNeish, Daniel

2017-01-01

In behavioral sciences broadly, estimating growth models with Bayesian methods is becoming increasingly common, especially to combat small samples common with longitudinal data. Although Mplus is becoming an increasingly common program for applied research employing Bayesian methods, the limited selection of prior distributions for the elements of…

The Determinants of Training in Australian Manufacturing SMEs

ERIC Educational Resources Information Center

Jones, Janice T.

2005-01-01

Purpose: The purpose of this article is to examine the factors influencing the provision of increased training in Australian manufacturing small and medium-sized enterprises (SMEs) that have embarked upon different growth development pathways. Design/Methodology/Approach: The longitudinal panel data employed in this research are drawn from the…

Roughness, resistance, and dispersion: Relationships in small streams

NASA Astrophysics Data System (ADS)

Noss, Christian; Lorke, Andreas

2016-04-01

Although relationships between roughness, flow, and transport processes in rivers and streams have been investigated for several decades, the prediction of flow resistance and longitudinal dispersion in small streams is still challenging. Major uncertainties in existing approaches for quantifying flow resistance and longitudinal dispersion at the reach scale arise from limitations in the characterization of riverbed roughness. In this study, we characterized the riverbed roughness in small moderate-gradient streams (0.1-0.5% bed slope) and investigated its effects on flow resistance and dispersion. We analyzed high-resolution transect-based measurements of stream depth and width, which resolved the complete roughness spectrum with scales ranging from the micro to the reach scale. Independently measured flow resistance and dispersion coefficients were mainly affected by roughness at spatial scales between the median grain size and the stream width, i.e., by roughness between the micro- and the mesoscale. We also compared our flow resistance measurements with calculations using various flow resistance equations. Flow resistance in our study streams was well approximated by the equations that were developed for high gradient streams (>1%) and it was overestimated by approaches developed for sand-bed streams with a smooth riverbed or ripple bed. This article was corrected on 10 MAY 2016. See the end of the full text for details.

Goal Engagement during the School-Work Transition: Beneficial for All, Particularly for Girls

ERIC Educational Resources Information Center

Haase, Claudia M.; Heckhausen, Jutta; Koller, Olaf

2008-01-01

The school-to-work transition presents a substantial regulatory challenge for youth in modern societies. Based on the action-phase model of developmental regulation, we investigated the effects of goal engagement on transition outcomes in a high-density longitudinal study of noncollege-bound German adolescents (N = 362). Career-related goal…

Effect of aircraft noise on the equilibrium of airport residents: Longitudinal study around Roissy, phase 3

NASA Technical Reports Server (NTRS)

Francois, J.

1981-01-01

The effects of airplane noise on the mental equilibrium of residents living near airports are discussed, and based on population sample surveys involving health questionnaires and self-administered personality tests. Progressive changes were observed on the part of residents living near a large airport.

Transfer, Lead, Look Inward: Further Study of Preservice School Librarians' Development

ERIC Educational Resources Information Center

Mardis, Marcia A.

2013-01-01

School librarianship is affected by the widespread challenges affecting schools and changing notions of school libraries' relevancy. The purpose of this study was to ascertain how these societal trends influenced educators' decisions to be school librarians. In this second phase of a longitudinal qualitative study, five school library program…

Embracing Technology: Learning a Foreign Language in Multimedia Environments.

ERIC Educational Resources Information Center

Shen, Hui Zhong

2003-01-01

Examines the experience of two young children learning Modern Standard Chinese (MSC) through playing in an unstructured home situation. Reports findings of their interaction with the software "The Language market." he research is the first phase of a longitudinal study of two young children learning MSC in a multimedia learning environment.…

Dynamic Creative Interaction Networks and Team Creativity Evolution: A Longitudinal Study

ERIC Educational Resources Information Center

Jiang, Hui; Zhang, Qing-Pu; Zhou, Yang

2018-01-01

To assess the dynamical effects of creative interaction networks on team creativity evolution, this paper elaborates a theoretical framework that links the key elements of creative interaction networks, including node, edge and network structure, to creativity in teams. The process of team creativity evolution is divided into four phases,…

Characterizing use-phase chemical releases, fate, and disposal for modeling longitudinal human exposures to consumer products

EPA Science Inventory

The US EPA’s Human Exposure Model (HEM) is an integrated modeling system to estimate human exposure to chemicals in household consumer products. HEM consists of multiple modules, which may be run either together, or independently. The Source-to-Dose (S2D) module in HEM use...

The power of a collaborative relationship between technical assistance providers and community prevention teams: A correlational and longitudinal study

PubMed Central

Chilenski, Sarah M.; Perkins, Daniel F.; Olson, Jonathan; Hoffman, Lesa; Feinberg, Mark E.; Greenberg, Mark; Welsh, Janet; Crowley, D. Max; Spoth, Richard

2015-01-01

Background Historically, effectiveness of community collaborative prevention efforts has been mixed. Consequently, research has been undertaken to better understand the factors that support their effectiveness; theory and some related empirical research suggests that the provision of technical assistance is one important supporting factor. The current study examines one aspect of technical assistance that may be important in supporting coalition effectiveness, the collaborative relationship between the technical assistance provider and site lead implementer. Methods Four and one-half years of data were collected from technical assistance providers and prevention team members from the 14 community prevention teams involved in the PROSPER project. Results Spearman correlation analyses with longitudinal data show that the levels of the collaborative relationship during one phase of collaborative team functioning associated with characteristics of internal team functioning in future phases. Conclusions Results suggest that community collaborative prevention work should consider the collaborative nature of the technical assistance provider – prevention community team relationship when designing and conducting technical assistance activities, and it may be important to continually assess these dynamics to support high quality implementation. PMID:26476860

Time-resolved imaging of the microbunching instability and energy spread at the Linac Coherent Light Source

DOE PAGES

Ratner, D.; Behrens, C.; Ding, Y.; ...

2015-03-09

The microbunching instability (MBI) is a well known problem for high brightness electron beams and has been observed at accelerator facilities around the world. Free-electron lasers (FELs) are particularly susceptible to MBI, which can distort the longitudinal phase space and increase the beam’s slice energy spread (SES). Past studies of MBI at the Linac Coherent Light Source (LCLS) relied on optical transition radiation to infer the existence of microbunching. With the development of the x-band transverse deflecting cavity (XTCAV), we can for the first time directly image the longitudinal phase space at the end of the accelerator and complete amore » comprehensive study of MBI, revealing both detailed MBI behavior as well as insights into mitigation schemes. The fine time resolution of the XTCAV also provides the first LCLS measurements of the final SES, a critical parameter for many advanced FEL schemes. As a result, detailed MBI and SES measurements can aid in understanding MBI mechanisms, benchmarking simulation codes, and designing future high- brightness accelerators.« less

Magnetic resonance separation imaging using a divided inversion recovery technique (DIRT).

PubMed

Goldfarb, James W

2010-04-01

The divided inversion recovery technique is an MRI separation method based on tissue T(1) relaxation differences. When tissue T(1) relaxation times are longer than the time between inversion pulses in a segmented inversion recovery pulse sequence, longitudinal magnetization does not pass through the null point. Prior to additional inversion pulses, longitudinal magnetization may have an opposite polarity. Spatial displacement of tissues in inversion recovery balanced steady-state free-precession imaging has been shown to be due to this magnetization phase change resulting from incomplete magnetization recovery. In this paper, it is shown how this phase change can be used to provide image separation. A pulse sequence parameter, the time between inversion pulses (T180), can be adjusted to provide water-fat or fluid separation. Example water-fat and fluid separation images of the head, heart, and abdomen are presented. The water-fat separation performance was investigated by comparing image intensities in short-axis divided inversion recovery technique images of the heart. Fat, blood, and fluid signal was suppressed to the background noise level. Additionally, the separation performance was not affected by main magnetic field inhomogeneities.

Space shuttle: Longitudinal and lateral aerodynamic characteristics of the 0.0035-scale GD/C aerospace booster (B-15B-1)

NASA Technical Reports Server (NTRS)

Debevoise, J. M.; Mcginnis, R. F.

1972-01-01

Force tests on a 0.0035-scale model of the General Dynamics/Convair space shuttle B-15B-1 booster were conducted in the MSFC trisonic wind tunnel during February and March 1971. Longitudinal and lateral characteristics were obtained at Mach numbers from 0.6 to 4.96. The configuration tested had a low delta wing, all-movable canard controls of delta planform, and a single vertical tail. Most of the test was devoted to obtaining data relevant to the transition from atmospheric reentry to subsonic cruise. In that portion of the test the angles of attack ranged from 6 degrees to 60 degrees, and yaw runs were made at angles of attack of 15 and 35 degrees. The rest of the test was devoted to obtaining booster-alone buildup data relevant to the launch phase. For the launch phase, the Mach number range was from 0.6 to 2.0, the angles of attack were from -10 to +10 degrees, and yaw runs were made at zero angle of attack.

Predator-induced synchrony in population oscillations of coexisting small mammal species.

PubMed

Korpimäki, Erkki; Norrdahl, Kai; Huitu, Otso; Klemola, Tero

2005-01-22

Comprehensive analyses of long-term (1977-2003) small-mammal abundance data from western Finland showed that populations of Microtus voles (field voles M. agrestis and sibling voles M. rossiaemeridionalis) voles, bank (Clethrionomys glareolus) and common shrews (Sorex araneus) fluctuated synchronously in 3 year population cycles. Time-series analyses indicated that interspecific synchrony is influenced strongly by density-dependent processes. Synchrony among Microtus and bank voles appeared additionally to be influenced by density-independent processes. To test whether interspecific synchronization through density-dependent processes is caused by predation, we experimentally reduced the densities of the main predators of small mammals in four large agricultural areas, and compared small mammal abundances in these to those in four control areas (2.5-3 km(2)) through a 3 year small-mammal population cycle. Predator reduction increased densities of the main prey species, Microtus voles, in all phases of the population cycle, while bank voles, the most important alternative prey of predators, responded positively only in the low and the increase phase. Manipulation also increased the autumn densities of water voles (Arvicola terrestris) in the increase phase of the cycle. No treatment effects were detected for common shrews or mice. Our results are in accordance with the alternative prey hypothesis, by which predators successively reduce the densities of both main and alternative prey species after the peak phase of small-mammal population cycles, thus inducing a synchronous low phase.

Development of longitudinally excited CO2 laser

NASA Astrophysics Data System (ADS)

Masroon, N. S.; Tanaka, M.; Tei, M.; Uno, K.; Tsuyama, M.; Nakano, H.

2018-05-01

Simple, compact, and affordable discharged-pumped CO2 laser controlled by a fast high voltage solid state switch has been developed. In this study, longitudinal excitation scheme has been adapted for simple configuration. In the longitudinal excitation scheme, the discharge is produced along the direction of the laser axis, and the electrodes are well separated with a small discharge cross-section. Triggered spark gap switch is usually used to switch out the high voltage because of simple and low cost. However, the triggered spark gap operates in the arc mode and suffer from recovery problem causing a short life time and low efficiency for high repetition rate operation. As a result, there is now considerable interest in replacing triggered spark gap switch with solid state switches. Solid state switches have significant advantages compared to triggered spark gap switch which include longer service lifetime, low cost and stable high trigger pulse. We have developed simple and low cost fast high voltage solid state switch that consists of series connected-MOSFETs. It has been installed to the longitudinally excited CO2 laser to realize the gap switch less operation. Characteristics of laser oscillation by varying the discharge length, charging voltage, capacitance and gas pressure have been evaluated. Longer discharge length produce high power of laser oscillation. Optimum charging voltage and gas pressure were existed for longitudinally excited CO2 laser.

Longitudinal mediation of processing speed on age-related change in memory and fluid intelligence.

PubMed

Robitaille, Annie; Piccinin, Andrea M; Muniz-Terrera, Graciela; Hoffman, Lesa; Johansson, Boo; Deeg, Dorly J H; Aartsen, Marja J; Comijs, Hannie C; Hofer, Scott M

2013-12-01

Age-related decline in processing speed has long been considered a key driver of cognitive aging. While the majority of empirical evidence for the processing speed hypothesis has been obtained from analyses of between-person age differences, longitudinal studies provide a direct test of within-person change. Using recent developments in longitudinal mediation analysis, we examine the speed-mediation hypothesis at both the within-and between-person levels in two longitudinal studies, Longitudinal Aging Study Amsterdam (LASA) and Origins of Variance in the Oldest-Old (OCTO-Twin). We found significant within-person indirect effects of change in age, such that increasing age was related to lower speed, which in turn relates to lower performance across repeated measures on other cognitive outcomes. Although between-person indirect effects were also significant in LASA, they were not in OCTO-Twin which is not unexpected given the age homogeneous nature of the OCTO-Twin data. A more in-depth examination through measures of effect size suggests that, for the LASA study, the within-person indirect effects were small and between-person indirect effects were consistently larger. These differing magnitudes of direct and indirect effects across levels demonstrate the importance of separating between- and within-person effects in evaluating theoretical models of age-related change. PsycINFO Database Record (c) 2013 APA, all rights reserved.

Compact Magic-T using microstrip-slotline transitions

NASA Technical Reports Server (NTRS)

U-Yen, Kongpop (Inventor); Wollack, Edward J. (Inventor); Doiron, Terence (Inventor); Moseley, Samuel H. (Inventor)

2010-01-01

The design of a compact low-loss Magic-T is described. The planar Magic-T incorporates a compact microstrip-slotline tee junction and small microstrip-slotline transition area to reduce slotline radiation. The Magic-T produces broadband in-phase and out-of-phase power combiner/divider responses, has low in-band insertion loss, and small in-band phase and amplitude imbalance.

Phase-relationships between scales in the perturbed turbulent boundary layer

NASA Astrophysics Data System (ADS)

Jacobi, I.; McKeon, B. J.

2017-12-01

The phase-relationship between large-scale motions and small-scale fluctuations in a non-equilibrium turbulent boundary layer was investigated. A zero-pressure-gradient flat plate turbulent boundary layer was perturbed by a short array of two-dimensional roughness elements, both statically, and under dynamic actuation. Within the compound, dynamic perturbation, the forcing generated a synthetic very-large-scale motion (VLSM) within the flow. The flow was decomposed by phase-locking the flow measurements to the roughness forcing, and the phase-relationship between the synthetic VLSM and remaining fluctuating scales was explored by correlation techniques. The general relationship between large- and small-scale motions in the perturbed flow, without phase-locking, was also examined. The synthetic large scale cohered with smaller scales in the flow via a phase-relationship that is similar to that of natural large scales in an unperturbed flow, but with a much stronger organizing effect. Cospectral techniques were employed to describe the physical implications of the perturbation on the relative orientation of large- and small-scale structures in the flow. The correlation and cospectral techniques provide tools for designing more efficient control strategies that can indirectly control small-scale motions via the large scales.

Detection of longitudinal ulcer using roughness value for computer aided diagnosis of Crohn's disease

NASA Astrophysics Data System (ADS)

Oda, Masahiro; Kitasaka, Takayuki; Furukawa, Kazuhiro; Watanabe, Osamu; Ando, Takafumi; Goto, Hidemi; Mori, Kensaku

2011-03-01

The purpose of this paper is to present a new method to detect ulcers, which is one of the symptoms of Crohn's disease, from CT images. Crohn's disease is an inflammatory disease of the digestive tract. Crohn's disease commonly affects the small intestine. An optical or a capsule endoscope is used for small intestine examinations. However, these endoscopes cannot pass through intestinal stenosis parts in some cases. A CT image based diagnosis allows a physician to observe whole intestine even if intestinal stenosis exists. However, because of the complicated shape of the small and large intestines, understanding of shapes of the intestines and lesion positions are difficult in the CT image based diagnosis. Computer-aided diagnosis system for Crohn's disease having automated lesion detection is required for efficient diagnosis. We propose an automated method to detect ulcers from CT images. Longitudinal ulcers make rough surface of the small and large intestinal wall. The rough surface consists of combination of convex and concave parts on the intestinal wall. We detect convex and concave parts on the intestinal wall by a blob and an inverse-blob structure enhancement filters. A lot of convex and concave parts concentrate on roughed parts. We introduce a roughness value to differentiate convex and concave parts concentrated on the roughed parts from the other on the intestinal wall. The roughness value effectively reduces false positives of ulcer detection. Experimental results showed that the proposed method can detect convex and concave parts on the ulcers.

Cellular and Muscular Growth Patterns During Sipunculan Development

PubMed Central

KRISTOF, ALEN; WOLLESEN, TIM; MAIOROVA, ANASTASSYA S.; WANNINGER, ANDREAS

2015-01-01

Sipuncula is a lophotrochozoan taxon with annelid affinities, albeit lacking segmentation of the adult body. Here, we present data on cell proliferation and myogenesis during development of three sipunculan species, Phascolosoma agassizii, Thysanocardia nigra, and Themiste pyroides. The first anlagen of the circular body wall muscles appear simultaneously and not subsequently as in the annelids. At the same time, the rudiments of four longitudinal retractor muscles appear. This supports the notion that four introvert retractors were part of the ancestral sipunculan bodyplan. The longitudinal muscle fibers form a pattern of densely arranged fibers around the retractor muscles, indicating that the latter evolved from modified longitudinal body wall muscles. For a short time interval, the distribution of S-phase mitotic cells shows a metameric pattern in the developing ventral nerve cord during the pelagosphera stage. This pattern disappears close to metamorphic competence. Our findings are congruent with data on sipunculan neurogenesis, as well as with recent molecular analyses that place Sipuncula within Annelida, and thus strongly support a segmental ancestry of Sipuncula. PMID:21246707

Anisotropy in the compressive mechanical properties of bovine cortical bone and the mineral and protein constituents.

PubMed

Novitskaya, Ekaterina; Chen, Po-Yu; Lee, Steve; Castro-Ceseña, Ana; Hirata, Gustavo; Lubarda, Vlado A; McKittrick, Joanna

2011-08-01

The mechanical properties of fully demineralized, fully deproteinized and untreated cortical bovine femur bone were investigated by compression testing in three anatomical directions (longitudinal, radial and transverse). The weighted sum of the stress-strain curves of the treated bones was far lower than that of the untreated bone, indicating a strong molecular and/or mechanical interaction between the collagen matrix and the mineral phase. Demineralization and deproteinization of the bone demonstrated that contiguous, stand-alone structures result, showing that bone can be considered an interpenetrating composite material. Structural features of the samples from all groups were studied by optical and scanning electron microscopy. Anisotropic mechanical properties were observed: the radial direction was found to be the strongest for untreated bone, while the longitudinal one was found to be the strongest for deproteinized and demineralized bones. A possible explanation for this phenomenon is the difference in bone microstructure in the radial and longitudinal directions. Copyright © 2011 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Simulation development and evaluation of an improved longitudinal velocity vector control wheel steering mode and electronic display format

NASA Technical Reports Server (NTRS)

Steinmetz, G. G.

1980-01-01

Using simulation, an improved longitudinal velocity vector control wheel steering mode and an improved electronic display format for an advanced flight system were developed and tested. Guidelines for the development phase were provided by test pilot critique summaries of the previous system. The results include performances from computer generated step column inputs across the full airplane speed and configuration envelope, as well as piloted performance results taken from a reference line tracking task and an approach to landing task conducted under various environmental conditions. The analysis of the results for the reference line tracking and approach to landing tasks indicates clearly detectable improvement in pilot tracking accuracy with a reduction in physical workload. The original objectives of upgrading the longitudinal axis of the velocity vector control wheel steering mode were successfully met when measured against the test pilot critique summaries and the original purpose outlined for this type of augment control mode.

Apparatus for high speed rotation of electrically operated devices

DOEpatents

Williams, Keith E.; Rogus, Arnold J.

1976-10-26

Most high speed centrifuges employ a relatively small diameter elongate flexible drive shaft, sometimes called a "quill" shaft. These relatively slender shafts are flexible to absorb vibration as the assembly passes through speeds of resonance and to permit re-alignment of the axis of rotation of the shaft and the rotor driven thereby in the event the center of mass of the rotor and shaft assembly is displaced from the nominal axis of the rotation. To use such an apparatus for testing electrical devices and components, electrical conductors for wires are passed from a slip ring assembly located at an end of the quill shaft remote from the rotor and longitudinally alongside the quill shaft to the electrical device mounted on the rotor. The longitudinally extending conductors are supported against the radially outward directed centrifugal forces by a plurality of strong, self-lubricating, slightly compressible wafers or washers co-axially stacked on the slender shaft and provided with radially offset longitudinally aligned openings to support the longitudinally extending conductors. The conductors are supported against the centrifugal forces and thus protected from rupture or other damage without restricting or constraining the essential flexure or bending of the drive shaft.

Axisymmetrical separator for separating particulate matter from a fluid carrying medium

DOEpatents

Linhardt, Hans D.

1984-09-04

A separator for separating particles carried in a fluid carrying medium is disclosed. The separator includes an elongated duct and associated openings incorporated in a solid body. The duct is axisymmetrical relative to its longitudinal axis, and includes a curved wall portion having a curved cross-section taken along the longitudinal axis. An axisymmetrical opening located downstream of the curved wall portion leads from the duct into an axisymmetrical channel which is substantially radially disposed relative to the longitudinal axis. Continuation of the duct downstream of the opening is a discharge portion which is substantially colinear with the longitudinal axis. In operation, a substantial majority of the fluid carrying medium leaves the duct radially through the opening and channel in a state substantially free of particles. A remaining small portion of the fluid carrying medium and a substantial majority of the particles are channelled into the discharge portion by centrifugal forces arising due to travel of the particles along the curved walls. For industrial scale separation of particles from a fluid carrying medium, such as for the clean-up of stack gases, an array of several hundred to several thousand of the separators is provided.

Experience of 49 longitudinal intestinal lengthening procedures for short bowel syndrome.

PubMed

Hosie, S; Loff, S; Wirth, H; Rapp, H-J; von Buch, C; Waag, K-L

2006-06-01

Forty-nine patients with a mean age of 25 months underwent a longitudinal intestinal lengthening procedure for short bowel syndrome (SBS) in our institution. Indications for the operation were dependence on parenteral nutrition in spite of adequate conservative management. The small bowel was lengthened from a mean of 27 cm to a mean of 51 cm. There was no intraoperative mortality. The following early complications occurred in our early series: ischemia of a short bowel segment of 2 cm, requiring resection in two patients, insufficiency of the longitudinal anastomosis in two patients and an intra-abdominal abscess in one. Four of 9 non-survivors died of liver failure and 3 of sepsis. Follow-up showed that 19 patients were weaned from parenteral nutrition after a mean of 9.1 months. Long-term complications encountered were dismotility with malabsorption due to bacterial overgrowth caused by progressive dilatation of the bowel, d-lactic acidosis, cholelithiasis and urolithiasis. A longitudinal intestinal lengthening procedure is an effective and safe surgical approach for SBS, provided it is performed in time, the patient's preoperative condition is optimized and technical surgical details are taken into account.

Longitudinal differentiation among pelagic populations in a planktic foraminifer

PubMed Central

Ujiié, Yurika; Asami, Takahiro; de Garidel-Thoron, Thibault; Liu, Hui; Ishitani, Yoshiyuki; de Vargas, Colomban

2012-01-01

Evolutionary processes in marine plankton have been assumed to be dependent on the oceanic circulation system, which transports plankton between populations in marine surface waters. Gene flow facilitated by oceanic currents along longitudinal gradients may efficiently impede genetic differentiation of pelagic populations in the absence of confounding marine environmental effects. However, how responsible oceanic currents are for the geographic distribution and dispersal of plankton is poorly understood. We examined the phylogeography of the planktic foraminifer Pulleniatina obliquiloculata in the Indo-Pacific Warm Pool (IPWP) by using partial small subunit ribosomal DNA (SSU rDNA) sequences. We found longitudinal clines in the frequencies of three distinct genetic types in the IPWP area. These frequencies were correlated with environmental factors that are characteristic of three water masses in the IPWP. Noteworthy, populations inhabiting longitudinally distant water masses at the Pacific and Indian sides of the IPWP were genetically different, despite transportation of individuals via oceanic currents. These results demonstrate that populations of pelagic plankton have diverged genetically among different water masses within a single climate zone. Changes of the oceanic circulation system could have impacted the geographic patterns of dispersal and divergence of pelagic plankton. PMID:22957176